"Let me have men about me that are fat;

Sleek-headed men and such as sleep o'nights:

Yond Cassius has a lean and hungry look;

He thinks too much: such men are dangerous."

Margaret Thatcher had about her Nigel Lawson who was then certainly fat, but seemed permanently in need of a hairdresser.

As for Tony Blair, he had about him Gordon Brown who was never sleek-headed, by all accounts still does not sleep o'nights and has never exactly looked lean and hungry. Brown duly did for Blair and in due course will, with poetic justice, do for Brown, too. Yet Lawson also helped to see off Thatcher.

Experience teaches me that you can't go by appearances. Dangerous men come in all shapes, sizes and hairdos, or none, in these shaven-skulled days, and may or may not enjoy a good night's kip. The ones you have to keep your eyes on are those who think too much.

Both Lawson and Brown thought too much as Chancellors and consequently blew it – Lawson by shadowing the Deutschmark and Brown by believing that money could be made to grow on family trees if you were stealthy enough in your Budgets.

In Lawson's case, he lost control of inflation. In Brown's case, he has lost control of public spending. By funding it with ever more taxes and borrowing – and encouraging the nation to live on tick – he has put us in a sticky position now that global capitalism's animal spirits have over-reached themselves and credit is hard to come by.

As Thatcher says, Lawson "did not generally like to seek or take advice" and "doubtless felt he did not need to".

Like Brown, he was disgracefully secretive about his Budgets, and no doubt Brown did not see why he should trouble Blair's pretty head with them.

If anything, Blair might have managed Brown better than Thatcher controlled her super-confident Chancellor. It took her nine months to discover what Lawson was up to in shadowing the D-mark behind both her back and the Cabinet's as part of an ambitious policy of international exchange rate stabilisation.

She found out only when a posse from the Financial Times came to interview her armed with a graph. From then on things went down hill, even though later Lawson fair took the nation's breath away by slashing the top rate of tax to 40 per cent where technically it remains.

A combination of inflation, no doubt boosted by Lawson's largesse for top-rate taxpayers, and the poll tax, eventually put Thatcher at the mercy of the Europhiles, the disappointed, the disgruntled and those in her Parliamentary party who
wanted a quieter life. Some of them got it at the expense of their seats.

This is the wilderness to which Gordon Brown is single-handedly leading his party, as the opinion polls seem to forecast. Like Lawson, he is well-endowed with brains and has a lively mind, even if it is curiously inflexible at the Dispatch Box.

The common failing of brainboxes who exercise them is often not just a lack of modesty, but an impatience with doing
the right boring thing, especially if it seems plodding and pedestrian.

Brown managed to do the right, boring plodding thing for the two years he undertook to stick by Kenneth Clarke's spending plans. Since then, under his tutelage – and nobody kids themselves that Chancellor Alistair Darling is anywhere else – we have become a nation grown vulnerably obese on tick, whether corporately as a nation or individually as householders and consumers. I do not blame Brown for America's sub-prime collapse, as the gross over-indulgence in lending is called. That is where his luck ran out. But clever men who are wise insure against bad luck instead of tempting it. He has failed miserably to do that. He will pay for it – and so shall we.

What we need now, whether fat, thin, hairy, sleek-headed, insomniac or slothful, are iron-willed politicians with their minds focused entirely on restoring prudence to our affairs. They are not called Brown or Darling. The longer they remain responsible, the longer it will take.

That is why the Tories are being so cannily careful not to promise tax cuts before they see the books.