In the long history of cognitive failure, Gordon Brown's response to the current expenses scandal must have a high place. The House of Commons, he asserted, could not continue to be a "gentleman's club." As everyone immediately realised, the Commons ought to have been exactly such a club, and alas, was not. No doubt, of course, it's quite hard to pin down what might characterise a "gentleman's club", but we do know that there are many things gentlemen will not do, and exploiting a set of rules for personal advantage is one of them.

It might seem that "gentleman" is a touch gendered in these feminist days to characterise the possible perfection of an assembly of whose members about one-sixth are female, but that would be a serious misunderstanding. In her celebrated book The Gentleman in Trollope: Individuality and Moral Conduct (Akadine Press, 1997), Shirley Letwin argued that the most perfect example of the uniquely English idea of the "gentleman" in Anthony Trollope's novels was Madame Max Goesler, who was probably Jewish, foreign and female. The figure of a gentleman, both as ideal and reality, is no respecter of genders. And that might make it a useful starting point in any treatment of the collapse of integrity in English politics today.

The crucial idea, however, is integrity itself, the moral core that guides us in judging appropriate limits to our pursuit of self-interest. Integrity is our faithfulness to the conception we have of ourselves as decent human beings. It not only comes in many shapes and sizes, but also wavers in response to circumstances. Nevertheless, it does tell most people in our culture that exploiting a set of rules for personal advantage is often a questionable thing to do. The notable absence of such integrity which has recently been so dramatically illustrated by a number of bankers and politicians makes it clear that British life faces not merely an economic and a political problem but, more basically, a moral one.

We need, then, to recover our moral bearings, and we may perhaps do so by starting from the one area of our lives where in fact no one believes the fashionable doctrine that morality is just a matter of choice and that virtues are optional. We must start, that is to say, with the professions. Whatever we may think about sex, perhaps, or about generosity to the starving of the world, no one doubts that the business of doctors is to do what is best for the patient. The doctor, in his medical identity, is an agent whose duty is selfless service, just as the accountant must give a true account of a company's real position in the balance sheet. To be "professional" in this way is to understand oneself, and to be understood by others, as worthy of respect for one's disinterestedness.

To be respected for such integrity is clearly a great benefit to any activity. One element of modern progress has been that many previously rather casually organised activities have set themselves up as professions. The tutors and governesses of an earlier time now belong to something called "the teaching profession", and activities ranging from surveying to estate agency have come to claim that they, too, belong in this admirable category. This movement has been part of a wider process in which so much of Western life has become laudably formalised, reliable in its results and for the most part "straight", which is to say, not corrupt.