Would the late Christopher Booker qualify as a “weirdo” in the Dominic Cummings sense? Certainly: although he was prey to deeply conservative, Housman-like stirrings over the English landscape, as well as passions for classical music and cricket, he was always ready to challenge orthodox thinking. And there was his abiding devotion to Carl Jung, which emerges in the epigraph (warning against “psychic epidemics”) to this, his last book, which has been edited and finished by Dr Richard North, Booker’s collaborator on his longstanding Sunday Telegraph column.

Booker started out in journalism as jazz critic of the Sunday Telegraph in 1959, in which capacity he once, in Boris-like fashion, wrote a fulsome review of a concert by pianist Erroll Garner despite it having been cancelled at the last minute. He was the first stand-alone editor of Private Eye from 1962 until the following year he was defenestrated by Richard Ingrams for abandoning the magazine to go on honeymoon with his aristocratic bride.

Although he later rejoined the Eye, as one of its anonymous parodists and jokesmiths, working in confabulation with Ingrams and Barry Fantoni, he also became a columnist for the Spectator, commenting on media matters, and standing back from the phenomenon of Sixties popular culture, of which Private Eye had been both exemplar, as spearhead of the “satire boom”, and critic.

His first book, published in 1969, was The Neophiliacs: A Study of the Revolution in English Life in the Fifties and Sixties. Modelled on Malcolm Muggeridge’s book The Thirties and deeply conservative in outlook, it bemoaned social developments as varied as rock’n’roll, supermarkets, liberalisation of the gambling laws, and James Bond movies, treating them as symptoms of a “psychic” epidemic, that term borrowed from Jung again.

Although its conclusions now seem overwrought, it was reprinted in 1992 and remains both a lively read and an intriguing snapshot of conservative thinking at the time. Groupthink is a natural successor to this earlier book and, indeed, repeats its central thesis in summary form. Yet it owes its title to another book, Victims of Groupthink (1972), by an American psychology professor at Yale, Irving Janis, who argued that “a group of people come to be fixated on some belief or view of the world which is hugely important to them. They are convinced that their opinion is so self-evidently right that no sensible person could disagree with it. Most telling of all, this leads them to treat all who differ from their beliefs with a peculiar kind of contemptuous hostility.”

Janis applied this theory to strategic blunders of US foreign policy, but for Booker the focus was different. The core of the book is a section about the history of political correctness that anyone who champions free speech will find to be an invaluable primer. He divides this history into five stages: the placid 1950s, the “liberated” ‘60s, the ‘60s “dream” giving way to frustration, the nightmare world of “diversity” and “multiculturalism”, and the eventual collision with reality that we are currently living through.

He would have been fascinated to witness part of the scientific establishment predicting 250,000 coronavirus deaths

As promoted by Donald Kennedy, president of Stanford University in California, in 1970, the birth of “multiculturalism” was accompanied by “a general climate of intimidation and fear”. Thereafter followed a steady stream of developments, from police and social workers turning a blind eye to a male Muslim rape culture in provincial England, to the unquestioning assumption of the merits of homosexual adoption, to the growth in perception of “hate crimes”, to trigger warnings, safe spaces and no-platforming at British universities.

It finally reached its apogee in persecution of anyone who maintained that gender was assigned at birth and not a social and cultural construct, or anyone who dared to oppose the notion of gender self-identification. Such heresy was deemed to be transphobia.

In her Channel 4 News interview about transphobia and gender politics in general with the Canadian academic Jordan Peterson, Cathy Newman “gave a perfect illustration of what happens to anyone who has become possessed by groupthink,” says Booker, in that “there will eventually come a moment when they are nonplussed and lost for words”.

From Booker’s Jungian perspective, the roots of all this absurdity can be traced to men and women losing their internal gender balance, whereby men become feminised in their headlong embrace of political correctness and women become aggressive harridans in their enforcement of it.

In typically dispassionate and lucid prose, Booker looks at historical examples of groupthink: Cromwell’s England, post-1789 France, Bonapartism, Soviet communism, Nazism, the foundation of the “European Project”, and the vicious orthodoxy surrounding man-made climate change, which he regarded as the biggest and costliest scare phenomenon of all time.

There is also a chapter on Darwinism: Booker did not argue against evolution, but opposed proselytising by evolution fanatics who “rest their case on nothing more than blind faith and unexamined a priori assumptions”.

Indeed, Booker would have been fascinated to live through the current coronavirus crisis and to witness how one part of the British scientific establishment, led by Professor Neil Ferguson of Imperial College London, predicted an extra 250,000 deaths without a lockdown and publicly excoriated, in a letter to the Financial Times, the less dramatic statistical modelling of Professor Sunetra Gupta and her team at Oxford University, essentially branding her as a “denier”.

In his Conclusion, Richard North warns that “we are moving from the age of enlightenment into a new era where leaden conformity with the prevailing groupthink is the dominant force in our lives”, but Booker thought differently. He believed, says North, that “every form of groupthink eventually has its day” and that “he was always willing to look on the bright side”.