Many politicians and pundits abandoned socialism and the Labour party in the 1970s, but there were few rightward shifts of allegiance more dramatic than that of Paul Johnson, the journalist and author, who has died aged 94. As a young man, Johnson stood on the left of the Labour party, made Aneurin Bevan the first object of his hero-worship, hymned the French rebels of 1968, and wrote that Tories were “atrophied Englishmen … on occasions, endearing – but liable to turn very nasty at short notice”.

Later he became an ardent supporter of Margaret Thatcher, and could sometimes turn nasty himself. A remarkably fluent and prolific writer, Johnson showed his vituperative gifts on the left before putting them at the highly paid service of Tory tabloids. In calmer mode, he was a reflective, elegiac and often moving writer about art, architecture and the English landscape.

The first of his popular histories was The Offshore Islanders (1972), a history of English people starting from the Roman occupation. It was followed at the rate of one a year by The Highland Jaunt, a journey in the footsteps of Johnson and Boswell written with George Gale, Elizabeth I, Pope John XXIII, and A History of Christianity (1976), a bestseller in several languages.

In 1975, he marked his dramatic break with the left and Labour by writing for the New Statesman a denunciation of a party at the mercy of the “know-nothing left” and the “fascist” anti-intellectualism of the unions, a theme on which he would expatiate with his usual eloquence and intemperance in Enemies of Society (1977). Like other defectors, he said he was dismayed by the power of the unions, and claimed, with characteristic hyperbole, that Labour was espousing a “corporatist” policy close to fascism. Johnson was soon writing as violently against Labour as he once had in its interest, and before long, the devotion he had once shown toward Bevan and then Harold Wilson had been transferred to Thatcher.

He attached himself to her as a mentor, saying later that she was “very ignorant in many ways” when she became prime minister, and needed to be taught, presumably by him. In 1980, he spent a year at the American Enterprise Institute, the rightwing thinktank in Washington, and he increasingly became a hero to the American right. This was sealed in 1983 by his book Modern Times, a fiercely “anti-relativist” or anti-progressive history of the 20th century.

Back home, Johnson wrote a weekly column for the Spectator, where he vented his spleen on the media and later on whichever subject took his fancy. He had a tendency to put his trust in princes who would eventually disappoint him, showering praise on Rupert Murdoch for years but later attacking his papers. On good weeks, Johnson’s Spectator columns were among the best things he wrote. Though he lacked the character of a real scholar, he was clever and widely read, with an old-fashioned well-stocked mind, so that he could turn out a polished column on almost any subject full of apt examples and pithy phrases.

That was to a lesser extent true of his far more lucrative “why-oh-whys” in the Daily Mail, attacking everything and everyone on the left. It was these fulminations that prompted Michael Foot’s jibe that, while every movement had its Judas, this was the first time the 30 pieces of silver had been turned into a weekly income. Tabloid editors who treated him with such reverence would have been dismayed by his private contempt for their papers. He once described from experience and with feeling the ordeal of the popular journalist, “writing to order, against a deadline, on a subject not of his choosing, for readers he does not respect and for an editor who is both demanding and gruesomely uncivilised”.

Johnson often wrote several thousand words a day. He was scornful of carping scholars who discounted his books, though these were sometimes slapdash. Intellectuals (1988) and Enemies of Society were diffuse tirades against half of the eminent thinkers of the Enlightenment and its inheritance, written with prurient personal abuse.

Some of Johnson’s “big books” were well written and readable, but uncritical in approach. After the History of Christianity, and what one critic called “Paul Johnson’s sycophantic” History of the Jews (1987), a colleague said that “Paul will now write a book telling the Americans how wonderful they are”, and he duly did. A History of the American People (1997) was “the most malignantly error-ridden” book of its kind, wrote Robert Sam Anson in the Guardian, “to appear since the politburo went out of business”, and it also achieved the unusual distinction of being criticised from a liberal perspective by Conrad Black.

He had a strong – if idiosyncratic – love of art; a collection of his Spectator columns was published as To Hell With Picasso! (1996). A keen painter as well as collector of watercolours, he wrote the excellent National Trust Book of English Castles (1978) and British Cathedrals (1980).

Born in Manchester, the son of Anne and William Johnson, Paul grew up in Tunstall, one of the potteries towns around Stoke-on-Trent; his father was principal of an art school in Burslem. He described his early upbringing In the Vanished Landscape: A 1930s Childhood in the Potteries (2004).

The family were devoutly Roman Catholic, and Paul won a scholarship to Stonyhurst, the Jesuit public school in Clitheroe. From there he went to Magdalen College, Oxford, where AJP Taylor was one of his tutors, and his friends included the gambler John Aspinall and the eventual Labour cabinet minister Tony Crosland. Having taken a second in history (1949), he was called up and commissioned into the Education Corps, serving in Gibraltar, and, unusually for a national service officer, becoming a captain.

Paul Johnson pictured in 1970. Photograph: Evening Standard/Getty Images

After demob, his first job was at the Paris magazine Réalités (1952-55). Then he joined the staff of the New Statesman, his home for the next 15 years. Johnson worked for Kingsley Martin, the very long-serving editor, and for his successor John Freeman, but he said that the man who taught him his trade was Aylmer Vallance, the assistant editor.

In the late 1950s Johnson combined magazine writing with television reporting, and then instant history. His first book, The Suez War (1957), was a denunciation of the previous year’s military adventure. For a time, he also tried his hand at fiction, with a couple of heavy-handed comic novels: Left of Centre (1960) and Merrie England (1964). Johnson chose wisely not to pursue fiction, although his enemies later liked to quote a lurid spanking scene from his brief oeuvre.

Despite that, he wrote a memorable onslaught on the James Bond books entitled Sex, Snobbery and Sadism (1958) in the New Statesman. In Johnson’s view, Dr No was “without doubt, the nastiest book I have ever read”, and he derided the Bond novels for their combination of “schoolboy sex fantasies” with suburban “snob-cravings”. This polemic caused Ian Fleming much distress.

In 1965 Johnson wrote another tirade, against pop music, “this apotheosis of inanity” whose fans were “the dull, the idle, the failures”, giving a hint of his later sea change. For all the years he would spend in popular journalism, Johnson was never a man of the people. Whether from left or right, he disliked the masses, their habits and their culture.

However, he was not quite the snob his detractors suggested: Johnson did enjoy the beau monde, but then he also relished the louche life of El Vino’s or of Muriel’s, the Colony Room drinking club in Soho. His first set of friends in London had been a group of rackety bohemian journalists, including Gale, Henry Fairlie, Colin Welch and Peregrine Worsthorne.

In 1965 Johnson was appointed editor of the New Statesman, despite the opposition of Leonard Woolf, a veteran board member. An old-fashioned sceptic, Woolf did not think a Catholic should have the job of editing a radical paper, even though Johnson was still a passable radical, denouncing the public schools and the House of Lords.

In many ways, Johnson proved a first-class editor. Even writers such as Alan Watkins and Neal Ascherson, disdainful of his later political turn, spoke admiringly of his skills at handling copy and encouraging talent. In Watkins’ words, he was “affable and tolerant as an editor”, and he had the supreme quality of loyalty to his staff, whom he always stood by without recrimination when there was trouble from bullying politicians or libel lawyers. Under Johnson, the New Statesman reached its highest circulation of 94,000, an astonishing figure in today’s journalistic climate.

While the kind of managerial socialism the NS espoused was itself discredited by the failures of the first Wilson government of 1964-70, Johnson nevertheless remained a loyal supporter of that government until its end. When Barbara Castle introduced her contentious plans for reforming industrial relations in 1968, he told a puzzled Statesman editorial conference that “Harold, Barbara and I are going to see this through”.

But he found the editor’s job exhausting. Behind his choleric appearance (like an explosion in a pubic-hair factory, in Jonathan Miller’s phrase), Johnson was highly strung, impulsive and prickly. He once told the African American writer James Baldwin that only someone like himself who was Catholic, redheaded and left-handed knew what prejudice meant. Drinking was one recourse, but that only served to increase Johnson’s bellicosity.

In 1970, he left the Statesman, and never held a salaried job again. He signed off with a collection of pieces from the magazine, Statesmen and Nations (1971).

In his later years, Johnson’s reputation was possibly higher outside his own country than within. He became celebrated in Latin America, like Eric Hobsbawm, ironically enough, with whom he could sometimes be seen conversing at literary parties. But his fame was greater still in the US. A large anthology of his writing was published with a glowing preface by William Buckley; Richard Nixon (whom Johnson always defended) gave Johnson’s books as Christmas presents; and the vice-president Dan Quayle extolled Modern Times as “one of the best historical books about history I have read”.

This ceaseless literary productivity continued with books as diverse as Wake Up Britain (1994), The Quest for God (1996), Napoleon (2002), Washington (2003) and Churchill (2009), and Heroes: From Alexander the Great to Mae West (2008). Later biographies ranged from Darwin (2010) via Stalin, Socrates and Mozart to Eisenhower (2014).

With all his gifts of intelligence and prodigious output, and his personal geniality and hospitality when in the mood, there could be something slightly unbalanced about Johnson’s verbal violence, and he suffered more than most journalists from a kind of cognitive dissonance. He angrily abused any politician who had fallen from sexual grace and advised his friend Diana, Princess of Wales, “Don’t commit adultery”, but brushed off untoward stories about himself by saying: “We are all sinners. Well, I am. That’s why I go to church every day.”

One of the last objects of Johnson’s hero worship was Tony Blair, who returned the admiration, writing, “Dear Paul, You’re quite simply one of the most remarkable people in our country.” In its way that was true enough. Whatever else was said of him, Johnson was a force to be reckoned with, and a true English eccentric.

In 1957 he married Marigold Hunt. She survives him, along with their three sons, Daniel, Luke and Cosmo, and daughter, Sophie.

Paul Bede Johnson, journalist and historian, born 2 November 1928; died 12 January 2023