But David Lipton was quite clear: the Fund has been saying for several years that the chancellor might have to slow the pace of deficit cuts if the economy continued to under-perform. In the staff's view, that day has now finally arrived.

The Fund doesn't think the chancellor should tear up his austerity plans or go back to square one. This is not a full-throated call for a Plan B. But as I suggested in April, that was never seriously on the cards.

What Mr Lipton and his colleagues have said is that it would be better for the economy and the government's long-term fiscal credibility if it did more to support growth this year - even if it means borrowing up to £10bn more, this year, than the chancellor currently plans.

That £10bn is the extra fiscal consolidation that is due to happen this year (i.e. the planned fall in the structural deficit - even though, as we know, total borrowing is likely to be broadly flat). The IMF thinks that implies an unwelcome "headwind to growth" which the chancellor can and should offset, including by bringing forward infrastructure spending.

Many of the measures the IMF has suggested have already been tried by the Treasury - I put it to the deputy IMF managing director that he was simply suggesting the chancellor do things they were already doing. He didn't accept my characterisation. He said, in terms, that the Treasury was talking about doing these things, but they were also very focussed on meeting their existing targets. In the Fund's view, he said, they should worry a bit less about the targets over the next year, and a bit more about supporting growth.

Again, we're not talking U-turns or a Plan B. This is not the mighty biff in the nose for the chancellor that the opposition might have been hoping for. There is much praise for the government here too. Crucially, the Fund doesn't think the government should slow the pace of deficit reduction overall - they still think the medium term plan makes sense. But it does, finally, think the chancellor should not just think about changing the pace of the austerity plans - but actually do it.

When I was first studying economics 25 years ago, my teachers were all expecting corporate taxes to disappear.

In a global economy in which capital and companies could go wherever they wanted, the assumption was that there would be an international "race to the bottom" when it came to corporate tax rates. Governments would either have to spend less or jack up personal income or consumption taxes instead.

Looking at the tax planning exploits of Amazon, Google and the rest, you might say the prediction had come true.

Except, corporate tax revenues overall have not fallen sharply as the world has become more globally integrated, or more digitally connected; rather the opposite.

IMF economists looked at this recently. They found that globalisation had pushed down corporate tax rates quite dramatically in the UK and around the developed world. (Especially in the 1980s - think of the successive corporate tax cuts under Nigel Lawson).

The median corporate tax rate in the largest 19 OECD countries fell from 50% in 1982 to 34% by 2003. But the researchers do not find this translating into lower corporate revenues: "...in fact, for the US and all regions save for Sub-Saharan Africa, revenues have risen over time."

Economists might not be surprised by that in itself. If corporate tax rates start out high, tax experts would say that cutting the marginal rate doesn't need to cost the government revenue, if the government broadens the tax base at the same time by cutting loopholes and deductions.

In large parts of the world, a lower rate might also encourage more black market companies to join the legitimate economy and pay tax for the first time. All of those things would tend to push up revenues, even if rates are going down.

But you can't usually raise revenues by cutting the tax on corporate profits to zero. With all the competition out there, economists might still wonder why corporate profit taxes are still with us at all, let alone be raising roughly the same amount as they were in the 1960s.

A chart (on p28 of the report) shows how corporate revenues have varied internationally since 1980 as a share of GDP. Predictably, the number jumps around a lot; corporate profits swing about wildly, depending on the economy, and you'd expect corporate tax revenues to do the same.

But, as I said, the prediction, 20-30 years ago would have been that in a global economy, revenues would be jumping around a fast-declining trend. That is not the picture you see on the chart. Before the financial crisis, OECD countries were raising significantly more from companies as a share of GDP than they were 30 years earlier. The average corporate tax take was 3.8% of GDP in 2007, up from 2.6% in 1990 and 2.1% in 1975.

Of course, you'd expect the financial crisis to have cut revenues. But corporate tax revenues, on average, were still 2.9% of GDP in 2010 (which is the most recent year available). In that year the chancellor raised 3.1% of GDP from UK companies - compared with 3.5% in 1990 and 2.2% in 1975. In the US, the figure was 2.7%, compared with 3.5% and 1990 and 2.9% in 1975.

None of this makes the tax exploits or Apple and the others any less disturbing, for voters or governments. Even Google's Eric Schmidt seems to agree that global tax rules have not kept pace with the development of the digital economy and they need to be reformed.

Individual countries care how much money they get from Google, relative to their sales. In economic terms, the interesting question is whether they are paying less than the average overall. It is quite possible that high-tech companies pay less tax, as a share of their global revenues, than the global average. I have not been able to find any research on this, either way, but you can't help feeling there ought to be some.

In the meantime, economists will continue to be puzzled that governments are still able to raise as much money from companies as they do. And governments, for their part, might be somewhat relieved that all the talk of scams and mounting avoidance has yet to seriously damage their capacity to tax companies overall. But companies that choose not to send their profits into the outer atmosphere - or any other offshore location - will not find that reassuring at all.

You could argue that it systematically biases the outcome against projects that will deliver benefits to people for a really long time.

Quite a few economists I know feel the same way. But none that I have spoken to thinks the economic case for HS2 is particularly strong.

"We should think of high-speed rail the same way we think about the Olympics," one of them said to me. "It's might just be a good way to make us all feel better about ourselves as a country. But we shouldn't kid ourselves that it's the most economically sensible way to spend £30bn."

And yet, as the National Audit Office (NAO) points out in today's report on HS2, the government's arguments for the project have tended to focus on the economic benefits to customers of increasing capacity and cutting journey times on the busy West Coast line.

Ministers have also stressed the broader economic and social benefits of building tighter connections between the North and the Midlands and the South-East. They talk about it being a "fast track to bridging the north-south divide".

There are also purported environmental benefits, with the government claiming it will help the UK meet its targets for cutting carbon emissions, though the NAO report suggests these will be rather small, and will depend on the way the electricity used to run the trains is generated.

Are the economic benefits worth the £30-35bn cost, in current prices, of building the network? The Department of Transport says they are.

Its own cost-benefit analysis suggests that every pound spent on the first stage to Birmingham would produce about £1.50 in benefits (depending on what you throw in). And they reckon the benefits of the second stage, further north, would be even greater - well over £2 for every £1 spent.

Critics have taken issue with the details of the analysis, particularly the assumption that time spent in trains by business travellers - counted as lost business time - is unproductive.

But for most economists, the scepticism about the economic case for HS2 goes well beyond the details of that elaborate calculation.

The point, for them, is not so much whether the benefits outweigh the costs - every government department and local council in the land could give you a list of projects that pass that test. The point is whether this is really the best one to be going ahead with, at a time when public capital spending generally is being cut.

Henry Overman, an LSE economist who has advised the Department of Transport on some of these issues, has written a useful summary of all this. It was written before the Department revised its case but the basic arguments still seem relevant.

At the time of the Eddington Review in 2006, he says the benefit-cost ratio for HS2 put it in the bottom fifth of investment projects that the Department for Transport had on its books. (And that is when the benefits of the first part of the project were said to be much higher than they are now).

That may all be true, supporters of HS2 would say, but what these narrow calculations are forgetting are the broader economic and social benefits that would come from this project, precisely because it is so big. It will so change the economic shape of the country - who knows what the ultimate results will be?

Who knows, indeed. Economists are not very good at capturing the broader dynamic benefits which might eventually stem from a project like this one. It's tricky to put a monetary value on the increase in national self-esteem that might come from the knowledge that we now have shiny fast trains too.

But, there is quite a lot of economic research into what helps to "bridge the North-South divide", and that does not suggest that high-speed rail is a particularly good way to do it.

That's because that high-speed rail line will, literally, go both ways. It might help northern companies compete more effectively with the South-East. But it might well also make it that much easier for the South to suck business and talent from the rest of the country.

This was brought home to me when I produced my report about the economy of London earlier this year.

By itself, the second stage of the project, connecting Birmingham to cities further north, might help boost economic connections between all those cities. But as long as it's all about giving these places an even faster link to London, the evidence from other countries suggests the majority of the direct and indirect economic benefits will go to the London and the South-East.

You might still say all this confirms how mean-minded economists are. Their cost-benefit analyses "discount" the future benefits - a pound of benefit for citizens in 50 years' time is worth a lot less than a pound today.

That is the standard way to do these kinds of calculations, since future generations are also likely to be a lot richer than we are. We can't invest infinite amounts now to help them. But you could argue that it systematically biases the outcome against projects that will deliver benefits to people for a really long time.

Looking back in history, it's hard to find many government "grand projets" that economists have liked (this book has a caustic summary of some of them).

The Millennium Dome is the famous recent example. But if ministers had only been concerned with the economics, we would not have had the Channel Tunnel. And we probably wouldn't have the Jubilee line extension or Crossrail either.

Note that many of those big projects involve trains. You would not have the same problem convincing the average economist of the case for expanding airport capacity in the South-East.

Governments like trains a lot more than we like airports, and so, apparently, do many voters. As I said at the start, plenty of economists like high-speed trains too. They just can't come up with a lot of economics to back that up.

But he and everyone else had hoped to see this kind of growth several years ago.

Even the new Bank forecasts don't show Britain's national output getting back to where it was before the crisis until the end of 2014 - and that's if we don't have a lot more bad news from across the Channel.

The Bank also expects inflation to be above the 2% target for at least another two years, at a time when earnings are growing at their slowest rate in more than a decade.

So household incomes will continue to be squeezed, even if the Bank's right that economy is now on the road to recovery.

Sir Mervyn's date with history

He was also a little more upbeat - to the extent that he was able to say the growth outlook had got slightly better since the last report, for the first time in more than five years.

There was an added dose of transparency in the Inflation Report itself, since we were given, for the first time, concrete numbers to go with the Bank's mesmerising fan charts.

That was supposed to make it easier for journalists and the city to see exactly what the Bank's new growth and inflation forecasts are. (Previously we had to use the charts to come up with our own numbers, with a sophisticated mathematical technique involving a ruler.)

So far, this does not seem to be quite the breakthrough we thought it was. Some city forecasters, like Citi, think the Bank is now forecasting growth of 1.3% in 2013.

But looking at the same figures, many other have concluded the 2013 forecast is now 1.1%. There's a range of views on the 2014 growth figure too, though it looks pretty close to 1.8%.

So much for greater clarity. But we can say for sure that the GDP forecasts are higher than they were three months ago, when the Bank was forecasting growth for 2013 of 0 .9%.

And they are a fair bit higher than the City consensus, which is currently for growth of 0.8% this year and 1.5% in 2014. We have not been able to say that for more than five years.

Did we learn anything else from Sir Mervyn's last turn at this event? Nothing earth-shattering, but a few outbursts of clarity from the governor are worth mentioning.

First, on the chancellor's new remit, which the governor welcomed and said provided a welcome "reaffirmation" of the 2% target for CPI inflation, as well as possibly removing uncertainty about the Bank's room for manoeuvre in deciding how to bring inflation back to that level.

Most people would say the MPC has had plenty of discretion over the past few years. Indeed, those who've been hammered by above-target inflation, month after month, might well say the Bank has had too much.

I asked the governor whether he thought the Bank would have done better with this more forgiving remit - and whether it would have helped the economy if inflation had gone even further above target, for longer.

He said the old target had given the Bank all the discretion it needed. He also said, flatly, that the MPC's policy would not have been any different if it had been following this new version of the remit all along.

If it wouldn't have made any difference in the past, you have to wonder whether it will make a blind bit of difference to policy under Governor Carney either - especially when you consider that eight of the nine members of the MPC after July will be the same as now.

Second, Sir Mervyn said the debate about George Osborne's austerity plans and the IMF had been "vastly overblown". Everyone, he said, seemed to agree that the UK and other countries needed a medium term plan for balancing the budget, plus automatic stabilisers to let borrowing respond to short-term setbacks for the economy.

Set against that big picture, the kind of adjustments being discussed in the whole IMF saga were pretty trivial.

He also dismissed European plans for a financial transaction tax out of hand, saying he had not spoken to any European central banker who thought it was a good idea. He also suggested that many of the politicians who had supported it in public were a lot more sceptical in private.

Finally and certainly most controversially, I can reveal that Sir Mervyn King today became the first senior central bank governor to publicly suggest that a country leave the eurozone. "You should come join the Sterling currency area", he said warmly, in responding to a question from a Slovenian journalist.

Unfortunately he was joking. Or at least, we are told he was joking. We may never know what he actually thinks.

Asked about Britain and the prospect of leaving the EU, the governor was less forthright.

He said it would not be right for him to share his view. It's a tough call, but that might be the least surprising thing he has said since he opened that first Inflation Report press conference all those years ago.

I wasn't at that first conference. But as a student intern at the Financial Times I did go to the third one, in August of 1993. I remember being suitably awed by my surroundings, and impressed by the then chief economist's willingness to answer our questions and also his apparent desire to explain the Bank's policy rather than simply repeat it.

Back then, Sir Mervyn reminded me of my university economics tutors - unsurprisingly, given that he had been a professor at the LSE before joining the Bank.

Twenty years on, the economic journalists who make their quarterly pilgrimage to this event are not so awestruck. You could say the relationship has 'matured'. He would say we were less respectful - downright rude, on occasion. For our part we hacks might say he was now a bit too defensive, a bit too unwilling ever to admit a mistake.

Time for a change, maybe. The inflation target and the Inflation Report itself are now under review, the Chancellor having asked the Bank's policymakers to consider whether and how the system could work better after the new governor, Mark Carney, takes over in July.

But as Mr Carney has said himself, in 1993 the Inflation Report and the UK inflation target were "state of the art". And it is not too much of a stretch to say that they helped to change the world. They certainly changed the world of central banking.

Like the inflation target - devised by Chancellor Norman Lamont in October 1993, after Britain's exit from the ERM - the Inflation Report was part of a global shift in central banking which the UK helped to lead. By making policy more transparent - and the people making it more accountable - the Bank's quarterly reports and press conferences also helped paved the way to central bank independence in 1997.

That greater transparency had a practical purpose: if the public understood the target and how the bank planned to achieve it, the idea was that households and wage earners would be more likely to believe in it - and if they believed in the new inflation target, it would be an awful lot easier to achieve.

To use the jargon, it was all about 'anchoring expectations'. And in that key respect you would have to say that the system that the UK helped to pioneer in the 1990s was a remarkable success - not just in the nice times before the crisis but pretty nasty ones

As you know, inflation expectations fell rapidly from the early 1990s onwards, in Britain and around the world. Inflation also fell, and became more stable. The one aided and abetted the other. What is interesting is that expectations have remained quite stable, even when inflation has been anything but.

At the time, many were astonished that the RPIX measure of inflation averaged just over 2.5% in the ten years from October 1999 - exactly on target. Sir Mervyn became Governor in the summer of 2003, the year when the Bank was asked to target a CPI inflation rate of 2%. in his first five year term, inflation averaged precisely that: 2%.

Since then, the average has been 3.2% - and inflation has been more than 1 percentage point above the target, more often than not. In fact, if the latest Bank forecasts are right, there will only be three quarters in the decade after 2005 when inflation was not above the Bank's target.

Why and how the Bank of England has been so wrong, for so long, has been the subject of much vigorous debate at these press conferences (and also in this blog).

You'll remember that Sir Mervyn tends to deploy two rather different lines of defence: the first is that the inflation overshoots have largely come from unexpected factors like higher energy prices or the rise in VAT, which the Bank could not have been expected to predict - and, he will add, most city forecasters didn't either.

His second argument is that even if the Bank had expected that higher inflation, it would not have chosen to do anything about it, because tackling that kind of externally generated inflation would have done too much extra damage to the domestic economy.

Critics say he can't have both - either the Bank knowingly set out to miss the target, or it didn't. In the quarterly press conferences, such critics tend to get short shrift.

The inflation debate among academic economists in Europe and the US is somewhat different. There the surprise has been, not that inflation has been so high, but why it has not fallen into negative territory, despite the depressed state of the economy and persistently high unemployment (see, for example, this paper from the IMF). I hope to say more on that in a future post.

But for central bankers and economists here and around the world, it's worth saying that what has NOT happened to inflation expectations in the past five years is almost as interesting as what has happened to inflation itself.

As the chart shows - long-term expectations of inflation in the UK have barely budged in the past decade, despite several years, before the crisis when inflation came in below target, and many since when inflation has come in too high.

Banks have failed. The global financial system has teetered on the brink of collapse. And consumers have seen the effect, month after month, in shrinking real pay packets and spiralling bills. But through all that, the average person in the UK has continued to expect the Bank to do its job - and continued to expect that inflation will eventually come back down.

There are lots of reasons why our expectations have remained so well 'anchored' - against the odds. But perhaps posterity will say that Sir Mervyn presided over 82 of them.

That is partly a reflection of how UKIP - and the eurozone crisis - have changed the terms of the European debate.

But arguably, the tensions have been there at the heart of the single market project right from the start.

For some, like the Deputy Prime Minister Nick Clegg, membership of the single market is a key economic argument for keeping Britain in the EU.

For others, like Lord Lawson, the regulatory burdens associated with the single market are a big reason why being in Europe is now doing us more harm than good.

As I pointed out last week, there is a middle way, in theory. We could be like Norway, which is part of the European Economic Area and enjoys access to the single market without being in the EU.

But, funnily enough, both sides seem to hate that idea, because we'd lose any power to shape the rules of the single market but still have to abide by them.

So, the politics of the single market right now seem rather black and white, even if the legal reality is not.

When it comes to the single market it's in or out. And for all the sound and fury, a majority of Britain's senior politicians - Labour, Liberal Democrat and Conservative - still seem to think that the economic benefits of being in the world's biggest single trading bloc outweigh the costs.

But - and this is a big but - the more thoughtful supporters of Britain's EU membership, including at least one cabinet member I've spoken to, also recognise that support for the single market is not nearly as easy as it used to be. And that is not just because of the eurozone crisis.

Why? Because if you believe - as Britain has always said it does - in the economic benefits of the single market, you have also to want to develop it further.

From where we are now, that is quite likely to mean more of the aspects of European integration that voters say they don't like.

Jo Johnson MP, the prime minister's new Number 10 strategist, said last year that the single market was one of Europe's greatest achievements, and completing it was "one of Europe's best hopes for economic growth".

He cited evidence that this would make the average European household 4,200 euros (£3,570) better off each year.

How, exactly, would we get those benefits? Well, here are the four pillars of the single market. You tell me which, if any, the average UK voter would like to see a lot more of:

Most of the single market's success so far has been in the free movement of goods and persons (rather too many persons, UKIP supporters would say).

Where it has made least progress is in services. Services now account for around 70% of national output in the EU but more than 90% are purchased from home-country providers.

Fans say the potential gains to opening up European services would be significant - and the UK, with its more efficient and less regulated services sector, would gain more than most from opening this up to European competition.

But, to put it crudely, UK accountants and others are only going to get those benefits if we also make it easier for not just plumbers but Polish management consultants and accountants to ply their trade here in the UK.

That is indeed a crude summary. But you get the idea. Even the most Europhile ministers, looking at what would actually be involved in deepening the single market for services, wonder whether now is really the right time to push ahead.

Many would say the same applies to the second pillar - harmonisation or mutual recognition of EU laws and regulations.

This is one of the most often mentioned benefits of the project for UK companies - that they only need to comply with one set of standards or regulations in producing and selling their products, rather than 27.

In the past the UK has preferred to do this through mutual recognition of other members' standards, rather than hammering out one harmonised approach.

But in practice, the single market involves both. So here, too, extending the single market is likely to produce more examples of "Brussels meddling" for Eurosceptics to pounce on - even if it also produces benefits for UK consumers and companies.

Or, there's the especially thorny issue of creating a single market in financial services, another British strong suit which has been greatly complicated by the eurozone crisis. Not to mention promoting the "free flow of capital".

It has been a while since the UK government felt able to push for these things in Brussels with any real enthusiasm.

Arguably, when it comes to banking regulation, the UK has become more nationalistic, in the wake of the financial crisis, not less.

Does all of this mean that Nick Clegg is wrong and Lord Lawson is right - that the single market is now more trouble than it's worth? Not necessarily. It does suggest that supporting the single market is no longer the soft option.

For decades, members of the UK establishment who didn't want a United States of Europe could agree that they did want a single European market - including, famously, Margaret Thatcher, who signed the Single European Act into law all those years ago.

Many in Whitehall and the broader business community would say the same today. But promoting the single market today is far from being the path of least resistance on Europe - and perhaps it never was.

You might also be interested to know that the Office for National Statistics (ONS) has moved a step closer to revising away last year's double dip recession.

Today's trade figures for March show UK exports rising, and the gap between our exports and our imports narrowed somewhat, though we should remember it is still massive by historical standards.

Exports to non-European markets grew 10% on the previous month, with exports to the US up by more than 20%, though exports to EU countries were broadly flat.

On the basis of these figures, some in the city think our net trade with the rest of the world may turn out to have made a positive contribution to Britain's growth in the first three months of the year.

Others are more cautious. But if it didn't actively detract from growth in the first quarter, that itself would be a big improvement on 2012.

We have also had the latest unofficial (but reputable) estimate of monthly growth from the National Institute for Economic Social Research (NIESR).

It reckons that national output grew by 0.8% in the three months to the end of April, up from growth of 0.3% in the three months to the end of March.

As NIESR economists are quick to point out, that 0.8% figure is being pushed up by the fact that January was so weak.

They don't think the underlying growth rate is anything like that fast, which is why they are yet to revise up their forecast of 0.9% growth for 2013 overall.

Still, it looks like we won't be talking about the possibility of a "triple dip" recession for a while - and not just because it now looks even more likely that the second of those dips is going to be revised away.

I flagged this up a while ago.

You'll remember that the second dip formally started with a fall in GDP in the last three months 2011 which has been gradually been revised into a decline of just 0.1%. The fall in output in the first three months of 2012 is also now 0.1%, and that in itself is a rounding up of the underlying number.

As I said in that earlier blog, the ONS only needed to revise that figure for the first quarter of 2012 by a few hundredths of a percentage point for the double dip recession to disappear.

With today's revised construction output data, the statisticians seem now to have reason to do just that.

The release shows construction output in the first quarter of 2012 has been revised up by 0.4%.

Even though construction accounts for less than 7% of national output, that change would be enough to turn minus 0.1% into 0.0% in the GDP figures for the first quarter of 2012.

The ONS says it is also planning to make further small adjustments to the data - to adjust for what they have decided is extra "seasonality" in the construction numbers.

That could actually make the GDP figure for the start of 2012 very slightly positive.

Or that's the theory - though, of course, there might be other changes to the data in the next month or so, which change the picture again.

We won't know for sure until the "Blue Book" national accounts figures come out on June 27th. But right now it looks as though the UK has not formally been in recession since the summer of 2009.

It is also the answer to most questions about the economic costs and benefits of staying in. These are not questions that economists or anyone else can give a sensible answer to - not least, because no-one can say with any confidence what the terms of Britain's NON-membership of the EU would be.

The deputy prime minister has suggested that three million jobs "rely directly on our participation" in the European single market. The source for this number is not entirely clear - though the number is similar to past estimates of the number of jobs that are directly or indirectly dependent on Britain's trade with the EU.

The Fullfact website has some useful due diligence on the subject.

To state the obvious: those jobs would not necessarily disappear if the country left the EU. Norway, for example, has access to the single market without being formally part of the EU.

Economists get a bit irritated when these debates are framed in terms of the "jobs at risk". What should matter, in the view of most economists, is what all this means for our rate of growth and our national income per head - in other words, what should matter is how our relationship with the EU is likely to affect our national prosperity. What a given level of income means for the quantity and quality of Britain's jobs depends not on the EU but on how our labour market works.

I suspect this is a lost cause for the economists. Most politicians will tend to talk about the economic impact in terms of jobs, and so will most voters. The point is that even if jobs were lost, we cannot assume that all those people would suddenly be out of work.

Lord Lawson and other supporters of British withdrawal would say that lifting the burden of European bureaucracy would create a lot more employment, and income - and open the eyes of British business to the many opportunities available outside Europe.

That is possible. It is also possible that being outside an increasingly integrated European Union would fundamentally undermine the City as a global financial centre and cause many global businesses to quit the UK. All of this is worth debating, and no doubt will be, here and elsewhere, in the years to come.

The relative economic costs and benefits of membership would be uncertain, even if we knew exactly what the terms of Britain's departure would be.

But when Britain's future - inside or outside the club - is so uncertain, it is difficult to even know where to start.

The euro rose in value, around the time the rate decision was announced, only to fall through the floor later on during the ECB President's press conference, falling 0.7% against the dollar in not very much time at all.

Does that market reaction make any sense? Not really. Long-term, as I've argued in the past, it's hard for most economists to see the eurozone's 17 economies coming through this without a weak currency.

Rebuilding their competitiveness within the eurozone is hard enough for the periphery countries, without the added disadvantage, in world markets of a strong exchange rate.

That is one reason why you might be puzzled that the euro has usually gone down at the worst moments of the crisis - and risen in value when policy makers seem to be pulling together.

But that is a long-term issue.

Today's fall in the value of the euro is surprising for a different reason - because it suggests that financial markets think the ECB is preparing to take more dramatic steps to support the eurozone economy.

That is quite possible. But I did not hear much in Mario Draghi's press conference to suggest it is now a lot more likely than it was before.

He said the ECB was "technically ready" to take the interest rate on its deposit facility into negative territory - in other words, to charge banks to park their cash with the central bank.

Interesting, but he's said it before.

He also said the ECB had "decided to start consultations with other European institutions" on measures to promote non-bank lending to companies by trying to revive that side of the asset-backed securities market.

Many had been hoping the ECB would move in this direction. But it's been talked about for months.

And Draghi later stressed that the consultations had not got very far.

In general, he seemed to want to talk down expectations of more unconventional measures from the ECB, not ramp them up.

It's possible the euro fell, not because of any of these comments, but as a result of the ECB President's general insistence that the ECB remained "ready to act" if further bad economic news suggested it was warranted.

So, investors might think, this might be the first of several cuts in the various interest rates that the ECB controls.

Maybe. But standing "ready to act" has been the ECB's watchword for a long time now. It was "ready to act" with the Outright Monetary Transactions for the crisis economies last summer - with miraculous consequences for European financial markets.

It's been a while since it did a lot of acting.

The refinancing rate that the ECB cut today has been at 0.75% since last July: Higher than the Federal Reserve's main policy rate, and the Bank of Japan's, and the Bank of England's. It was 1% until December 2011.

The European Central Bank has cut its key interest rate by one half of one percentage point, in 17 months. In those 17 months, inflation in the eurozone has fallen from 2.7% to 1.2%, and the eurozone economy, overall, has shrunk by around 0.75% - with much steeper falls in the crisis economies and at least another year of recession predicted for many countries.

Puzzle all you like about what the ECB might be about to do next. We shouldn't forget to be surprised that it has taken so long to do even this.

It's a puzzle for economists everywhere, and there's no better example than this week's hotly anticipated European Central Bank meeting.

"Everyone is so excited about whether the ECB will cut rates," Michala Marcussen, head of global economics for Societe Generale, told me. "You have to wonder why - when everyone also seems to agree that a rate cut will not do much to help the real economy."

The answer to the riddle is that it might not help the real economy, but it's a fair bet that it will help equities. In fact, that is probably why the markets have been rising on bad economic news - because, other things equal, bad news suggests that central banks will keep the markets bathed in super-cheap liquidity for that much longer.

But, you might well ask, doesn't the real economy eventually have to start to reward all that market optimism? Don't European companies eventually have to start delivering the revenue and earnings growth built into all those rising share prices?

That is the big question hanging over the ECB meeting today and over all European policymakers, waiting for any sign that the depressed eurozone economies are on the mend.

Politicians and officials have generally been happy to have the market run ahead of the real economy in the past six months, because they felt that the more positive mood would turn into a self-fulfilling prophesy. Higher confidence would beget lower borrowing costs, which would beget rising lending to companies, which would finally lead to some growth.

Has that happened? Well, the first part of the chain has. Borrowing costs in the distressed economies have fallen for firms and governments.

But not nearly as much as the markets have risen. And that improvement in credit conditions has yet to offset the deflationary impact of continued fiscal austerity, which - if anything - will be greater in 2013 than it was in 2012 in countries such as Spain and Portugal.

Last week, the average unemployment rate for the eurozone as a whole hit 12.1%. It's less than half that figure in Germany - just 5.4%. While in Spain, the rate of joblessness is now pushing 27% - with youth unemployment much higher than that.

Mario Draghi has again made clear in recent speeches that fixing the structural economic problems of Spain and the rest cannot be the job of the ECB. But he has also said the ECB will continue to fight the balkanisation of European finance.

These charts from a recent speech by ECB Vice-President Vitor Constancio show that, although borrowing costs have fallen in much of the periphery when it comes to households and companies, there's still a wide gap between German interest rates and rates at the periphery.

In the jargon, the "transmission mechanism" for the ECB's monetary policy is still impaired, and credit is still crunched in the countries that need it most. All of which may help to explain why market expectations surrounding this ECB meeting have been so high - and expectations among economists are so low.

Cooler heads are entitled to point out that our national output shrank by the same amount in the previous three months before. In a sense, Thursday's figure simply reverses that fall.

It's true that the decline in the fourth quarter of 2012 was almost entirely due to the unwinding of the Olympics effect over the summer. But the perception that the recovery does not have a lot of momentum behind it is not just down to special factors like the weather or the Olympics.

Even with Thursday's growth news, the UK's GDP is only 0.6% bigger than it was a year ago. The Office for National Statistics says it has been "broadly flat" for the past 18 months - and our economy is still 2.6% smaller than it was before the start of the recession five years ago.

Just as troubling, the manufacturing sector is smaller than it was at the start of 2013 - let alone 2008. The figures show production in this part of the economy shrank by 0.3% in the first quarter - and is 0.3% smaller than when the Chancellor took office.

The services sector did the work, as usual, and does not seem to have been badly hit by the poor weather.

At the Chelmsford garden centre I visited for my piece for Thursday evening's TV bulletins, the owner, James Richmond, told me that business had fallen off a lot in the cold winds of March. But he would probably not be surprised to hear that services companies like his have expanded overall. Footfall at his centre is higher than last year, even though spending per head is slightly down.

The construction sector was clearly hit hard by the weather. Simon Ward, chief economist at Henderson, points out that overall GDP would have risen by 0.48% if construction output had been stable in the first three months of the year, as you might have expected on the basis of rising orders figures at the end of 2012.

He reckons that the quarterly GDP figure, on average, has been revised up by 0.15% since the start of 2009 (that's comparing the first estimate with the latest version). Taking both considerations into account, he says, "true" growth may have been 0.5% or more.

That is not what many others are saying. But it does now seem quite likely that the ONS will revise away last year's "double dip" recession. The change in GDP in the last quarter of 2011 was recently revised from minus 0.4% to minus 0.1%.

The official figure for the quarter after that - the first three months of 2012 - is also now minus 0.1%. And that is a rounding up of the actual figure, which shows output falling by just 0.07%. So, an upward revision of less than 0.05% of that first quarter figure would be enough to eliminate last year's recession.

So much for past history. What about the future?

If we carry on growing at this pace, the economy would grow by around 1.2% - easily beating the Office for Budget Responsibility's forecast for 2013 for growth of 0.6%. But as recently as December, that forecast was, err... 1.2%. And even that would not take the economy back to where it was pre-crisis.

City forecasters have their own views on whether the economy can continue growing at this rate, with some markedly less optimistic than Henderson's Simon Ward.

Looking at other official data and private business surveys, the consensus forecast before this number came out was for growth of just 0.1%. So it's fair to say that before Thursday morning's GDP data, most forecasters thought the recovery had less momentum behind it than these official figures suggest - not more.

So it is good news. We can say, now, that plans for a modest recovery in 2013 remain on track. But no sign, yet, that we are about to race ahead.

Which side is right? Unless or until the Scottish people vote for independence, we'll never know. Each is certainly overstating their case.

What their true negotiating position would be after Scottish independence is another thing we cannot know unless or until it actually happens. But even their pre-referendum arguments each have a grain of truth.

If you're a country, how do you decide whether to have the same currency as your neighbour?

Economists usually say the downsides to having a different currency are higher transaction costs and, potentially greater macroeconomic instability.

Companies have to worry about fluctuating exchange rates when they do deals across the border. And it costs everyone a little more to visit or do business with the other country.

As a government with its own independent currency, you also have to build your own credibility in world markets. If you share with another country, you have more chance of trading on their good name.

But there are also important upsides to currency independence - the largest being that when your central bank sets interest rates, it only has to worry about economic conditions here at home. It doesn't need to think about other countries that might be doing better or worse, or accept interest rates that have been set elsewhere.

Through history, countries have weighed up these two competing considerations: the greater stability and lower transaction costs that come with sharing your currency or fixing the exchange rate, versus the benefits of setting your own course (and interest rates).

The fact that currency arrangements have changed so much, and so dramatically, over the centuries, tells us the trade-off is tricky, and can change over time. If we didn't know that before, we have learned the lesson again, looking at what's happened with the eurozone.

When the euro was launched, at the turn of the century, most economists would probably have said the economic case for some of the 17 members signing was a lot stronger than others. In purely economic terms, it made a lot more sense for Austria to share a currency with Germany than it did for Greece.

Austria's economy was quite similar to Germany's in the late 1990s, in income terms and its levels of productivity. The two economies also tended to move together, over the course of the cycle. For good measure, they also spoke the same language and had a history of people moving back and forth across the border.

You could not say the same of Greece, which had much lower output and income per head, and an entirely different kind of economy to Germany. Currency union between Germany and Austria made quite a lot of economic sense - a union between Germany and Greece, rather less so, whatever the political arguments in favour.

I use the examples of Greece and Austria because each is only slightly larger, in economic terms, than Scotland would be, in the event of independence. Likewise, the difference in size between them and Germany is similar to the gap between Scotland and the rest of the UK.

Within the union, the Treasury paper basically says the current set-up for Scotland makes sense, for the same reasons that a currency union between Austria and Germany makes sense - though I should say they never make the comparison. The two economies are structurally very similar. They move together. And there's a lot of back and forth - of trade and people - between the two. Same language, too (give or take).

But if and when Scotland became independent, the paper suggests that a lot of those advantages would evaporate. Why? Primarily because without the financial transfers and political credibility that comes with being part of a single UK, Scotland's economy would be much more vulnerable to shocks, and less able to raise funds cheaply in world markets to even out the bumps.

Scotland's heavy reliance on North Sea oil and the financial sector for its revenues would, say the Treasury, make Scotland's economy much more volatile than the UK.

As I pointed out in a piece for BBC News at 10 on Monday, UK growth has been pushed down quite a lot recently by declining North Sea oil and gas output. Without it, the onshore economy would not even have had a double dip recession last year.

If it had been an independent country over the past decade, with a geographical share of oil and gas revenues, the impact of the recent fall in North Sea output on Scotland's tax revenues and overall economic growth would have been more dramatic.

Over time, the Treasury says the two countries would be less and less well synchronised if Scotland were independent. A currency union between Scotland and the rest of the UK would start to look less like Germany and Austria - a bit more like Germany and Greece.

There is little mention of Greece or Austria in the Treasury paper. But the basic argument is the same: supporters of Scottish independence are suggesting you can have your cake and eat it too.

The paper asserts that Scotland cannot have all the extra autonomy over taxes and spending and regulation that comes with independence, while somehow also hanging on to all the benefits of sharing a currency with the rest of the UK, because currency union after independence would have to work differently than it does now.

There would not be the same automatic fiscal transfers, helping to keep the two economies in sync. There would need to be a fiscal pact, and a clear agreement about how - and when - the Bank of England would ever bail out Scottish banks.

The Scottish government accepts the last part of this, that there would need to be a deal on fiscal policy and the banks. It disagrees that it would be so onerous for Scotland - or unattractive to the rest of the UK.

Economists might have sympathy with that second point. What George Osborne said on the Today programme on Tuesday morning was actually stronger than the report itself. He said it was "unlikely that a eurozone-style currency union with Scotland could be made to work" after independence.

It is not obvious, given the practical and economic advantages of currency union highlighted in the report, why that would be the case, if Scotland were willing to sign up to a Treasury-style set of constraints.

As I said at the start, we don't really know what the negotiations would look like in the event that Scotland actually chooses independence, and what we've heard on Tuesday may not provide much of a clue.

It's not entirely plausible that Westminster would turn its nose up at a currency union with Scotland, in those circumstances. But nor is the idea that Scotland could win significant economic freedom as an independent country - without giving up anything significant in return.

I pointed out yesterday that revisions had already eliminated the £100m fall in the chancellor's preferred measure of borrowing between 2011-12 and 2012-13.

Not only will we discover on Thursday whether the UK has formally gone back into recession, but on Tuesday we might learn that government borrowing rose in 2012-13, after all.

I don't get the impression that serious investors are hanging on the fund's every word on the subject either.

Though the claimant count fell slightly, employment is down - and the wider measure of joblessness rose 70,000 in the three months to February.

For the advanced economies as a group, the IMF is now expecting a slightly slower recovery than it was in January, with growth of 1.2% in 2013 and 2.2% in 2014.

For me, the lesson of all that talk is that it is a very difficult question to answer without caveats and qualifications, and not just for the usual reason, that her policies "divided the nation". It's also because the market economy she helped to bring to the UK is itself such a many-sided thing.