The names of Tory MPs who are retiring at the election reads as if a census had been taken at Camelot. Twenty-eight knights of shire and suburb, 18 members of the Privy Council, nine also-rans and Steve Norris are to quit. That makes a total, so far, of 57 members of the 1922 Committee. A veteran or two will remain (providing they survive the election), including Sir Marcus Fox and Sir Geoffrey Johnson Smith. What will such a purge do to the post-election Tory party?

I was first elected to Parliament as MP for Rochester and Chatham in October 1959. The Tory party was led by Harold Macmillan, whose bad teeth, shabby cardigan and elegant deviousness set the tone for a five-year Parliament. His necktie bore the stripes of the Brigade of Guards. Until the 1930s there was a phrase common in the Brigade, "to be as brave as a Macmillan". But in the early Sixties, when his government lost popularity, he stood in need of all his courage.

The run-of-the-mill Tory MP had had "a good war"; some still used their military rank. The party's backbench defence committee attracted a formidable body of military men. Today, there is not a soldier in the party. Forty years ago, the average Tory had gone into politics as an extension of his sense of social obligation. He did not seek office. He was content to serve, either in the Whips' Office, which in those days consisted of one-time adjutants of good regiments, or, more simply, as the party's ballast.

David Maxwell Fyfe (described by Macmillan as "the stupidest man I have ever met") once proclaimed that loyalty was the party's secret weapon. He was to be proved disastrously wrong. In fact, and in recent years, disloyalty has come to be the Conservative Party's not-so-secret weapon.

I have prints taken from two pictures of the House of Commons. The first, painted in 1960, and presented to the Prime Minister by the 1922 Committee as a gesture of thanks for winning the 1959 election, shows the Tory benches as black as a convention of undertakers. The uniform worn was black trousers, black, hand-made shoes and striped jackets. Ties, when they were not of an instantly recognisable stripe, were of City silver. In my picture a confident Macmillan is seen at the despatch box, lord of all he surveys. The old actor-manager was at his peak.

The second painting, done in the mid-Eighties, shows a very different picture. The undertakers have given way to birds, if not of paradise, then of prey. White handkerchiefs have become blue suits a lighter shade of pale; shoes, either brown or grey. It is impossible to tell a Conservative MP from a Labour colleague.

Were a third picture to be painted circa 1996, it would owe more to Bacon than to Botticelli. The new breed of Conservative combines something of Steve Norris, a little of Edwina Currie and a good deal of David Mellor. The Government backbenches are packed with hard-faced young men flaunting their ideology, either in favour of the untrammelled forces of the market, or of hostility to all things pertaining to Europe, like so many mobile telephones.

They all seek office, or, if not, lucrative consultancies. The looming figure of Bill Cash, a man with the biggest feet in England, Sir Teddy Taylor and James Cran would, as one man, raise their tattered banner. Only Sir James Goldsmith would be missing.

What will disappear with the election, whether or not the Tories win or lose, is idealism. The old One Nation Conservative will be in a small minority; the pro-Europeans, who wanted to build a New Europe with Britain enjoying a prominent place within it, will have retired to their Sunset Homes. We were the children of Hitler's war; we wanted to bring to an end the enmity between France and Germany which had been the cause of two catastrophic wars. We saw Europe as the only alternative to a steady political and economic decline. Not all of us were federalists (whatever that ill-used word might mean), but we were intelligent patriots, never nationalists. We despised populism, and sought civil harmony.

One has only to glance at the list of names of those who will quit politics to see how grave a loss their departure will entail. Douglas Hurd, David Howell, Kenneth Baker, Paddy Mayhew and George Walden, all of whom have striven to keep the ship afloat. It is particularly sad that Richard Ryder, until recently the Chief Whip, is to abandon politics. He suffers from a bad back. His career could have been a glittering one. At least his successor, Keith Simpson, is an intelligent moderate. But Simpson is the exception to the rule.

The Euro-sceptics, that party within a party funded in part by Lady Thatcher, have recently made great play with the "fact" that the bulk of the new Tory candidates are against a common currency. I have not been privy to their researches, such as they are, but I fear that they are probably correct.

A brief look at the names of those who will succeed fills me with gloom. Eric Forth will be returned for Chislehurst. Oliver Letwin, a clever right- winger, will, in all likelihood, take the place of Sir James Spicer. Were the Government to be returned with a large majority, the newcomers would make up a New Model Army. But such a victory is hardly likely: we would do well to scrape home. Defeat on any scale would leave a disenchanted rump of Tories that would look either to Portillo or Redwood as its new leader, and by so doing, condemn a great party to 20 years in the wilderness. Which, I can only conclude, would be the best place for it.

Sir Julian Critchley is the Conservative MP for Aldershot. He, too, is retiring at the election.