Analysis By Robert Peston Business editor, BBC News

Gordon Brown could fear a tax black hole if corporate tax is cut

Banks make a surprising amount of money out of the "can't be bothered" factor.

They frequently offer us worse than the best deals available, because we often can't be bothered to move our accounts to earn a few extra pounds.

And guess what? The "can't be bothered" factor also operates at the level of the entire economy.

Or to put it another way, our Government is able to levy a bit more tax and impose a bit more irksome regulation on companies than the most competitive countries.

And the explanation is that most businesses can't be bothered to move their head offices to Dublin or Bermuda - where taxes and regulations are less burdensome - because it's just too much trouble to do so.

Tipping point

But there comes a point for all of us when it becomes wholly irrational not to move because the savings on offer elsewhere are just too big to ignore.

And the �100bn question for Gordon Brown, as he hosts the first meeting of his strangely-named "High Level Group", is whether the moment is approaching when the UK economy is perceived to be too uncompetitive.

This High Level group largely consists of the senior executives of the leading firms in the City of London, the heart of the UK's financial services industry - and they are the most mobile companies in the UK.

If these citizens of the world come to believe that the advantages of being in London were outweighed by the disadvantages, you can forget about them remaining here out of any great patriotic sense.

Will HSBC bar the doors of its UK operations?

As it happens, they always bellyache about the meddling of ministers and regulators. It's in their nature to see any constraints on their business as unnecessary.

But these days their moaning is a few decibels louder.

The UK's largest bank, HSBC, has mused out loud about how it could save a fortune in tax if it relocated abroad.

And one of the world's great investment banks, Merrill Lynch, has recently increased the importance of its Dublin-based operations relative to those in London.

Keep them sweet

The Treasury is very bothered by all this.

The last thing it wants to see is the undermining of the British economy's great success story, the City.

So the minister for the City, Ed Balls - whose brain is hotwired to the Chancellor's - has been having breakfast, lunch and tea with the bankers.

And he has been reassuring them of his Churchillian resolve to see off attempts by US or continental regulators to undermine our competitiveness by foisting burdensome new rules on our firms.

But what about tax?

Can he - will he - urge Gordon Brown to cut the bill for companies when there are so many other competing claims on precious revenues?

That's still unresolved - though Messrs Balls and Brown are keeping a wary eye on David Cameron.

Mr Cameron's Tax Commission wants to see a sharp reduction in company taxation and the abolition of stamp duty on share trading - which tests his determination to make no tax pledges.