Company taxes at Budget heart
Part of the background to today's Budget is a growing concern that businesses in Britain are paying too much tax and that the tax system here is a bit too complicated.
For example - and as I wrote here last night - it has emerged that the head office of the giant bank being created by the merger under negotiation between Barclays and ABN would be in the Netherlands.
That means that the new superbank would probably be registered for tax purposes in the Netherlands, which over time would lead to quite a significant loss in tax to the Exchequer.
Now Barclays is being careful to say that the decision hasn't been taken. And it is very keen not to lay into the chancellor at this delicate juncture.
But accountants tell me that it would be mad not to base itself in the Netherlands, because the tax advantages would be huge.
So part of what the chancellor will attempt to do today is restore the competitiveness of the UK in a tax sense.
According to the CBI, in 1997 the UK had the third lowest rate of corporation tax among the 15 countries which were then members of the European Union.
At the time, Gordon Brown took very public pride in cutting the corporation-tax rate.
However the headline corporation tax rate has been unchanged at 30% since 2000, while other countries have been cutting their tax rates.
Today, the UK's corporation tax rate is the seventh highest among the current 27 members of the EU.
It's important not to overstate the gravity of our fall down this league table.
The tax rates of some of our very biggest competitors remain higher than ours, as does the actual burden of taxation (which includes the impact of all taxes on companies, not just corporation tax).
The Treasury for example is keen to point out that the UK still has the lowest rate among the G7 leading global economies. And for example the tax burden on companies in Germany and France remains significantly higher than it is in the UK.
But the trend, of the UK becoming less competitive when it comes to company taxes, is clear and unambiguous.
Among the chancellor's great obsessions of the moment is that the British economy mustn't become less competitive at a time of intense worldwide competition for the best jobs between countries.
I therefore expect him to announce measures in the Budget to lift Britain's position in the league table of tax competitiveness.
That could mean that the rate of corporation tax would be cut over time - and almost certainly that steps will be taken to reduce the complexity of the tax system.
If he does do that - and as I say, the odds of something happening in that direction are high - the shadow chancellor, George Osborne, would be able to do the "I-told-you-so" dance.
On Monday, he urged the chancellor to cut three pence off the headline rate of corporation tax, funded mainly by a streamlining between the allowances the tax man gives companies for wear and tear or depreciation of physical assets and the rate at which companies in practice write off those assets.
Osborne's suggestion highlights perhaps the most important constraint on Brown's tax reforming ambitions. The chancellor simply doesn't have the money available to cut taxes unless he can boost revenues to the Exchequer in other ways or cut outgoings.
So whatever he does would probably be a long term process. And it would be funded by constraining the growth of public spending or finding compensating revenues.