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It's thought the Chancellor will find some more money for social care.

We need to look out for "how much" and will it be enough to stave-off the more immediate pressures, said Richard Humphries, a Senior Fellow at the King's Fund, a charity which campaigns for better health care in the UK. 

He also says we should examine the time scale of any new funds, what strings might be attached and ask, is this really new money?

In case you want to liven up the Chancellor's speech, William Hill has drawn up the "Philip Hammond Word Game".

Surely there will also be mentions of a "stronger, fairer Britain", "feeling the pinch", and a few gags at the opposition parties' expense.

Image source, AP

Chancellor Philip Hammond is using a box designed and created for his predecessor, George Osborne, back in 2011.

Osborne used Gladstone’s 1859 budget box for his first budget in June 2010 but it’s now been retired to the Cabinet War Rooms after fears the handle might drop off during the photoshoot.  

Mr Hammond is not the first Chancellor to not use the original Budget box.

James Callaghan, who was Chancellor between 1964 and 1967, said the Gladstone Box was too small and had a bigger one made in brown leather.

Gordon Brown also used a new case, which was built by four trainees in his constituency of Kirkcaldy and Cowdenbeath.

The 2011 case was ordered by the National Archives and was built by London firm Barrow and Gale.

The Chancellor holds the red Budget box aloft - assuming the traditional Budget day pose. 

Philip Hammond is currently making the short journey - by car - from Downing Street to the Houses of Parliament.

Law firm Eversheds Sutherland reckons - and they're not alone in saying this - the government needs to take another look at the business rates system. 

Speaking up for retailers, the firm says the sector is facing a range of threats to consumer confidence too.

The Prime Minister has announced another of the policies that will be unveiled in today's Budget.

There will be £5m to help parents return to work after a long career break, Theresa May said on  parenting forum Mumsnet, external . The fund will be open to men and women - but the PM expects it'll largely be taken up by mothers.

There will also be £20m to tackle domestic violence, Mrs May said. 

BBC 5 live has done the number crunching for us. Click play to see how much the national debt is still going up...

But Andrew Sentance, a former member of the Bank of England's interest-rate setting committee, puts this in some context. By historical standards, the debt as a proportion of economic output is below average... 

Image source, Press Association

Today's Budget will be the last one to take place in the spring.

Apart from Ken Clarke's Autumn Budgets between 1993 and 1996, and an emergency post-war Budget in 1945, Budgets have always been held in the spring.

The need for a Chancellor to give a annual financial statement was introduced by Sir Robert Walpole in the 1720s.

The spring date wasn't just to coincide with the new financial year. In the 18th century much of the country's wealth derived from agriculture, and Budget day was timed because the collection of the Land Tax took place in April.

Chancellor Philip Hammond will be hoping that the move to autumn won't result in a similar fate to that which befell Walpole's predecessor, John Aislabie, who was Chancellor between 1718 and 1721.

He was imprisoned in the Tower of London after wrecking the nation's finances during the South Sea bubble.

The political fallout from that resulted in the annual financial statement we know today as the Budget.

Image source, PA

As you know, from now own we're only having one Budget - in the autumn - not a Budget in the spring plus a mini-budget (or Autumn Statement) in November. Most people welcomed the news from the Chancellor last year that there would be less frequent tinkering.

But the Chartered Institute of Management Accountants doesn't think that goes far enough. They want just two interventions per parliament.

We should forget the Budget, says Jonathan Riley, head of tax at accountancy and professional services firm Grant Thornton.

Instead of looking at "meagre giveaways" we should look at how living standards will be affected by economic pressures, he says.

UK shares are straying from positive to negative territory and back again ahead of the Budget announcement at 12:30.

The FTSE 100 is up about 0.12% at 7,347.87 points.

Legal and General shares have dipped about 1.5%, despite this morning reporting a rise in profits for last year.

But G4S shares are up more than 6% after it reported 14% higher profits. It's in the FTSE 250.

Laura Kuenssberg
BBC political editor

BBC Business Live

Hetal Mehta, senior European economist for Legal & General Investment Management, told the BBC's Business Live programme:

"One of the key things is that the economy has performed much better not just since the referendum but even the Autumn Statement we had last November.

"So the Chancellor has a lot more wriggle room. Tax revenues have been higher, so he could use that."

But she doesn't think he will.

"I think he's been quite clear, he's unlikely going to go on a spending spree. He's going to keep that money in reserve. Remember Brexit still hasn't actually happened yet. So if and when the economy does deteriorate the government has got something up its sleeve."

She thinks that's wise.  

Rupert Harrison, former Chancellor George Osborne's  chief of staff, writes: 

Image source, Getty Images

Batten down the hatches.

Markets could have a "turbulent" few hours as Philip Hammond delivers his Budget, says Paul Sirani of traders Xtrade.

"Key to affecting the strength of the pound could be the expected announcement of a so-called 'Rainy Day Fund'. The more money, supposedly around £60bn, that Philip Hammond can set aside for steadying the ship as it sails out of the single market, the more likely the pound is to hold its own." 

He adds that Mr Hammond's plan for business rates is "crucial".

"With UK businesses beginning to feel the effects of rising inflation, both in their own running costs and the slowdown in consumer spending, many will be expecting him to lower rates. If businesses are left to battle through Brexit under the current system, then the Chancellor is at risk of eroding confidence in the economy," he says.