The terminal variety of rot set in on 17 October 1963, according to Geoffrey Wheatcroft, as a result of Harold Macmillan's machinations to make the 14th Earl of Home his successor as prime minister and leader of the Conservative Party. Until then, the old aristocratic Tory order had happily embraced the aspiring middle class and professional high-flyers who, in turn, were only too pleased to join the gentleman's club - quite literally, in the case of Macmillan's cabinet colleague Iain Macleod, the doctor's son who was by then a much-cherished member of White's, the most exclusive of all the St James's Street establishments. The appointment of Alec Douglas-Home as leader badly ruffled the newly acquired fine feathers of Macleod and fellow middle-class cabinet ministers who had fancied themselves for the top job. To them, the unexpected choice of a 14th Earl was a quite over-the-top affirmation of aristocratic cheek, a gratuitous breach of the convention that preserved this plum for one of their own.
Macmillan had form in this respect. Only a year earlier, in an appointment described by its beneficiary as "the greatest act of nepotism ever", he had made his nephew-in-law, the 11th Duke of Devonshire, a minister of state. But this being only a junior job, it had caused more amusement than offence, and was at worst seen as eccentric. The prime ministership was a different matter, and Macleod, abandoning any further social ambitions, decided to break rank. In a blistering article in the Spectator - then a rather weightier political journal than it is today - he played the anti-aristocratic card for all it was worth, setting off a fatal class war within the ranks of the Conservative Party that has raged on, with disastrous consequences, for more than 40 years.
Nothing has been the same since. The historic marriage between aristocratic authority (privilege justified by service) and bourgeois dynamism (careers open to talent), which had been the secret of the Tory party's longevity and enabled it to grow far stronger roots than the merely right-wing political parties on the Continent, was irrevocably damaged. Home lost the next election, leading to the disastrous leadership of Edward Heath, which in turn paved the way for the bourgeois trium-phalism of Margaret Thatcher. Her utterly un-Tory ideological excesses left such a bad taste in the mouth of the English people as to make Conservatism henceforth unpalatable, except as a last resort in the absence of a less dire alternative.
I oversimplify. Wheatcroft is far too subtle and learned a historian to tell the political history of the Conservative Party in the past half-century in quite such stark terms. However, underlying his immensely readable and sardonic account can be discerned the author's realisation that English Conservatism was not in any way doctrinal or ideological, but instead depended on an idiosyncratic way of acting and thinking rooted in a particular social hierarchy. Without that hierarchy, English Conservatism would not work, which explains the Tory party's determination to preserve our peculiar class system. Personal interest came into it, but so did the knowledge that, without an aristocratic ingredient, the Conservative Party would lose not only its magic but its very raison d'etre.
What about Thatcher: did she not try to reinvent the party? Most certainly she did. She changed it from a party that had always had grave reservations about capitalism - rightly fearing that it could prove even more destructive of civilisation than socialism - to a party unreservedly enthusiastic about free markets. As it happened, such a party was just what was needed to take on the trade-union militants. But once that task was successfully completed, and the Iron Lady's years of destiny had come and gone, the country was left in the hands of a group of free-market zealots from whose ranks most of the old-style paternalists had been banished. A new breed of greedy careerists had taken over. Whereas, in the old days, Conservative MPs were somebodies before they were elected, now they were only somebodies because they were elected.
Not since the days following the First World War, when Conservative MPs were said to look like men who had done well out of the war, had the Tory back benches seemed filled by such an ill-favoured bunch of crooks, bigots and weirdos. Nor were the Conservative newspapers spared the ravages of this blight, because it was at this time that the formerly commonsensical and irreproachably respectable Daily and Sunday Telegraphs fell into the hands of the now notorious Conrad Black. So long as Thatcher was leader, her formidable individual strengths and virtues disguised the lamentable state of the party, which was made all too shamefully obvious by the cowardly manner of her eventual dethronement.
It was no wonder that, as soon as Tony Blair had weaned the Labour Party off socialism, the electorate showed the Conservatives the door, as they probably will again. Which is unfortunate because, without the fear of socialism to keep capitalism in check, old Tory types, still wedded to an ethos that preceded the capitalist era, are sorely needed throughout public life - even in the armed forces. As it is, the only people left to chasten corporate greed are the Christian Lords Spiritual, whose withered shoulders are almost laughably unfit to bear so enormous a responsibility.
On a lighter note, Wheatcroft offers good stories and perceptive comments on almost every page. There is even one about Winston Churchill that I have never heard before. The writer Kenneth Rose was commanding a troop of Welsh Guards tanks in the final offensive into Germany in 1945 when they drew up to listen to Churchill's orations. "Advance Britannia!" he said. After a pause, the troop ser-geant was heard saying: "Sounds as if the old bugger's pissed."
Another enjoyable one is about Edward Heath, who became an opposition whip in 1951 thanks to the abrupt departure of Sir Walter Bromley-Davenport. One evening, Bromley-Davenport spotted a well-dressed man leaving the Palace of Westminster. Taking him to be a recalcitrant Tory ignoring the vote, he tried to make him stop and, when he did not, kicked him downstairs. When the man turned out to be not a Conservative MP but the Belgian ambassador, Bromley-Davenport's career as a whip ended and in stepped Heath.
William Hague also receives a ribbing. Wheatcroft dismisses his schoolboy address to the Tory party conference in 1977 as "gruesomely precocious", and mocks his suggestion that Heathrow be renamed Princess Diana Airport as "limply bathetic". One puts the book down chuckling, as well as feeling wiser and better-informed. Roll on Wheatcroft's next volume - entitled, one hopes, The Not So Strange Death of Blairite England.
Peregrine Worsthorne's most recent book, In Defence of Aristocracy, is published by HarperCollins