Brian Taylor
Political editor, Scotland

To cross questioning. Alistair Darling started with the currency - and a further demand for Plan B.

Mr Salmond said there were three plan Bs: a flexible currency, a currency fixed to the pound and unilateral use of the pound. The FM repeatedly noted that Mr Darling had agreed that Scotland could not be stopped from using the pound.

In this section, Mr Salmond repeatedly tried to turn it round and demand answers from Mr Darling. Would he support a sterling zone in the event of a Yes vote? The FM wanted the same comment as delivered by Jackson Carlaw of the Tories who said he would man the barricades for a sterling zone in the event of independence.

Mr Darling said alternatives to the Union involved rotten currency options.

Mr Darling's second question focused on oil. The debate was feisty - but with no common ground. Mr Darling talked of estimates below that used by the Scottish Government. Mr Salmond disputed that - and referred repeatedly to Mr Darling's tenure as Chancellor.

Robert Nugent: All the topics under discussion are secondary to the key question of whether an independent Scotland has sufficient tax revenue to finance all their plans and what that implies for tax rates.

Charles Campbell: Why should a voter give any credibility to the politically biased views of a politician whose party sold out to the city of London and who, having crashed the economy and having failed to supervise the banks, took ownership of HBOS and RBS (at huge expense and indebtedness to the taxpayer) without exercising control and instituting any meaningful reform?

George Taylor: This referendum should be cancelled. With only a few weeks to go, we, the electorate still don't know what we are being asked to choose. No clear answers on currency, Europe, NATO, armed forces etc. This is the first election in history when nobody knows what they're choosing.

Only two questions from Alistair Darling during his cross-examination. Now it is Alex Salmond's turn.

He asks "how many children are moving into poverty by the UK government's welfare reforms?"

Mr Salmond asks why Mr Darling is defending the Conservative-led government's policies.

Mr Darling says he does not support the current government's policies but he still believes the UK is the best chance of getting a fairer society.

Alistair Darling's cross-examination turns to oil revenues. If your oil revenues are £6bn less than expected in a single year, what would you do, asks the Better Together leader.

Mr Salmond says North Sea oil production is going up. He says you save money when you have more than you expect and spend it when you need to. He says Labour had a deficit of £150bn when Mr Darling was chancellor.

SNP MSP Humza Yousaf, external: Alistair Darling knows he's losing this he's flailing, shouting, wagging finger, going red in the face - they huff and they puff #bbcindyref

Scottish Conservatives MSP Murdo Fraser, external: Not sure the Salmond 'I am never wrong' approach will go down well with the voters #bbcindyref

Labour MP Lucy Powell, external: Just switched on. My ears hurt! #indyref

Craig Livingstone, external: #bbcindyref Ridiculous waste of cross examination from Darling...what is he doing? How many times does he need the same answer?

Matthew Crowther, external: Alex Salmond can't give an answer he just shouts popular things for a cheer. He doesn't seem to have any intelligence #bbcindyref

The currency is the foundation of our economy, Mr Darling says. Imagine you are wrong, he says, what is your plan B?

"Even your insults are retreads from the last debate," Mr Salmond says.

The first minister asks if the people of Scotland give him the mandate to have a currency union with the rest of the UK, would Mr Darling support that?

"We cannot be stopped from using the pound," says Mr Salmond.

"So that is plan B?" asks Mr Darling.

Andrew Black
Political reporter, BBC Scotland

Mr Salmond says Mr Darling's comments that an independent Scotland could use the pound is the most important revelation of the debate.

Mr Darling says the point is that an independent Scotland, without a currency union, would have little economic control.

On to the cross-examination. Alistair Darling starts.

He wants to raise the currency again, he says. The audience groans and Mr Salmond calls him a "one-trick pony".

Louise Sayers
BBC Scotland

Forty minutes into the debate, "Yes" voter Gillian Martin says: "There are so many more important things than currency. It's a red herring... Salmond has already set out a plan A, B, C and D."

James Bream, undecided, has been scribbling furiously during the currency discussion.

But he admits that the debate might not actually help him decide on how to vote, saying: "My decision might be what I feel on the day."

On welfare, Mr Salmond says the Scottish Parliament took £50m from other areas to compensate vulnerable Scots being penalised by the "bedroom tax".

Mr Darling says the so-called bedroom tax will be repealed by a future Labour government. But Alex Salmond accused Mr Darling of being "in bed with the Tories" in the Better Together campaign.

The Better Together leader says the UK is better together. Things are difficult just now but we would be making a huge mistake to take the risk of independence, says Mr Darling.

Referring to Mr Darling's example of shipbuilding jobs which come from being part of the UK, Mr Salmond says shipbuilding employment in Scotland has gone from "tens of thousands to three of thousands". How is that better together, he asks.

Emily Craig
Political analyst, BBC News

Alex Salmond started off by repeating a claim he made in the first debate. He says an independent Scotland would be the 14th richest economy in the OECD. This is about GDP per head (that's the total amount of goods and services produced by the economy divided by the population). The current rankings, external of GDP per head among OECD countries puts the UK in 18th place but the Yes campaign says with a geographical share of oil Scotland would rise up the ranks.

There's more BBC analysis here.

Shadow Chancellor of the Exchequer Ed Balls, external: There will be no currency union. Scotland would probably end up with the Euro - the least worst option for Scotland #BBCIndyRef

SNP MP Stewart Hosie, external: #bbcindyref. Darling now defending the UK Tory Government. Tory cuts to the NHS are OK now then are they? #voteyes

Emily Craig
Political analyst, BBC News

Alistair Darling says the NHS in Scotland has spent nearly £100m in the last couple of years on private sector providers. It's not immediately clear where this figure is from. Earlier this year the SNP's Health Secretary said, external the NHS had spent £28m on independent providers (0.8% of its total budget) in 2012/13. He added that this would fall to around £25m in 2013/14.

Calum Macdonald: I don't see why Scotland would not be able to adopt its own currency; you could simply call it the Scottish Pound. If all of the Scandinavian countries are able to function with their own respective currencies, then there is no reason why Scotland can't either.

Clive Chalk: Can you please put to Mr Salmond: If he maintains that the pound is equally as much Scotland's as rest of the Union, will he not also accept that UK oil equally belongs to the rest of the Union too?

"If we are Better Together, why are we not better together already?"

Alistair Darling says most people want to see a "strong and thriving health service". He says he is against going down a route that will see public services more squeezed than they would be by remaining part of the UK.

Mr Salmond asks if Mr Darling s the only person who "does not realise what is happening to the NHS in England and Wales".

Richard Woolley in Cheshire emails: The English will not allow their government to let Scotland use the pound. Scotland cannot have its cake and eat it. Independence means they are on their own.

I feel sorry for all the Scots who live in the rest of the UK who have been deprived of the vote.