The first Budget after a General Election is normally a nasty affair. It is the moment when a Chancellor can administer whatever unpleasantness he has in mind with the maximum chance the we will have forgotten about by the time the next election comes round.
This one is different. In all likelihood it is Gordon Brown's last. He has a high opinion of his historic status as a Chancellor - his admirers have looked back as far as Gladstone to find a better one, which may unsettle the ghost of the Grand Old Man. The last thing he has in mind is a grim, grinding, farewell Budget sorting out the unintended consequences of his earlier mistakes.
He wants to go out with a triumphant blast of the trumpet underwriting his claim to be Tony Blair's unchallengeable successor - very soon. He must be tempted to come up with a resonant surprise proclaiming himself as a visionary Chancellor rising above the complexities of his brief, multiplied over the past ten years by his own love of complexity.
The politics of surprise apart, there are two issues he cannot very well avoid, the pensions crisis, for which he must take a fair bit of the blame, and the lack of value for money for the billions he has lavished on the National Health Service.
For pensions, the one thing he won't do is unwind his original blunder depriving pension funds of tax relief on their dividends - costing them £5 billion a year in 1997 and a great deal more now.
Nor will he unscramble his means tests for pensioners, which provide an overwhelming disincentive for anyone on a moderate income to save up for their old age.
Most probably he will do what all sorts of people have been urging to do and switch a fair bit of the Government's borrowing into the long-dated securities which pension funds have been buying at grossly inflated prices because the new pensions regulator has been urging them to buy investments which match their long-term liabilities.
This has had the absurd effect of pushing yields on these stocks down to little more than one per cent above inflation. That in turn pushes up the capital sum actuaries say is needed to buy every £100 of a future pension - so the black hole of pension deficits gets deeper than ever.
If Mr Brown can change the pattern of his borrowing so as to boost the supply of these bonds by even one per cent, he could go some way to restoring the position of many stricken pension funds.
As to the NHS, it is hard to see what he can do except lecture them and threaten to bring in some new auditing system to spot money being frittered away before it is too late.
What he does not have to do is raise taxes. In his pre-Budget statement last December he doubled the special tax on North Sea oil profits. That, together with a hefty crop of income tax and corporation tax in January, seems to put him on course to meet his borrowing forecast of £37 billion for the 2005/06 tax year. In that event, he will probably leave the £34 billion borrowing pencilled in for 2006/07 alone, too.
Further out it may well be another matter - but a headache for another Chancellor.
So he shouldn't need to raise to raise taxes this time. Over-all, that is - he can and surely will, rob Peter to pay Paul.
Still, the CBI is sufficiently heartened by the improving look of the Government's finances to call for a cut in taxes on business - either a cut in the headline rate of corporation tax or a reversal of the extra one per cent on National Insurance contributions.
It would come as a huge surprise if Mr Brown took that advice. But then this could be a Budget of surprises - albeit with a nasty surprise in the small print to offset each pleasant one that catches the headlines.
Several business organisations have urged the Chancellor to take it easy on his drive to shut down tax loopholes on the grounds that this is turning into a pattern of creeping stealth taxes combined with a tangle of red tape. They argue that combined with rising taxes on business, it is damaging Britain's ability to compete Mr Brown is more likely to step up his campaign. He relishes the complexity of the fine points of tax law - and attacking tax dodgers plays well politically.
As for taxes on private individuals, a lot of the pre-Budget talk has been about inheritance tax. The housing boom has transformed what used to be a levy on the wealthy into a tax that over much of Britain will catch anyone who inherits a three-bedroom house.
Halifax calculates that 1.5 million homes, almost one in 12 of all owner-occupied properties, are worth more than £285,000, next year's starting point for IHT.
It reckons 35,000 estates are paying IHT this tax year, against 15,000 when Mr Brown moved into the Treasury. That is worth £3.3 billion rising to an estimated £3.6 billion in 2006/7 - more than the Mr Brown has pencilled in for beer and cider and level-pegging with capital gains tax.
That is precisely why it will be astonishing if he yields to demands for the IHT threshold to be linked to house prices. The money has become too good. He can argue, too, that
he did enough last year by promising to raise the starting point to £300,000 in 2007.
If he did relent any further, he could well claw back the lost revenue by scrapping the arrangement whereby heirs can re-arrange the terms of a will posthumously so as to minimise the tax liability.
That could be worth a lot of money. Nigel Lawson thought of doing that in the 1980s, but the outcry was such that he backed off and no other Chancellor has dared to try it since. Mr Brown would be less worried by that particular outcry and it would play well with Labour backbenchers who would welcome a consolation prize after the Education Bill fiasco.
There are still hopes that he may have some mercy for business. David John at PricewaterhouseCoopers thinks some good may be achieved just by simplifying the corporation tax system. Others have pleaded for a cut
in the headline rate, as other countries have been doing.
That might not require more money than Mr Brown can garner by another round of stealth taxes and closing up more loopholes.
One certainty is that he will have more to say about Child Trust Funds, one of his pet projects. He could make some promise about a top up gift from the taxpayer when children reach the age of seven. It will generate easy headlines without costing a penny for another five years.
But that can hardly be his big populist surprise. Nonparents resent it. Mr John tips the 2012 Olympics.
They are going to be a mess unless serious money is spent on transport to enable crowds to get anywhere near the site. Mr Brown could take credit now for finding cash that will have to be found anyway.
But whatever the surprise, rest assured, he will claw back the cost somewhere else.