I like Peter Hitchens. And judging from the reaction to my latest YouTube interview of the Mail on Sunday’s rightwing firebrand, this is a guilty secret shared by others on the left. We share little common ground – he is a proponent of a deeply pessimistic (or “relaxed”, as he would put it) social conservatism – though there is a mutual support for rail renationalisation and distaste for the modern Tory party. Yet, for different reasons, we both find ourselves outside the political consensus that combines free-market economics with social liberalism.

One of the most fascinating aspects of Hitchens is his political journey. A man who now regards the Conservative party as de facto socialist was once a godless Trotskyist, a member of the International Socialists (the forerunners of the Socialist Workers party), who were committed to the revolutionary overthrow of capitalism and the establishment of a workers’ state.

Peter Hitchens and Owen Jones discuss Jeremy Corbyn’s surge in popularity. Guardian

This was no brief dalliance: Hitchens was a member for many years, leaving in his mid-20s. He now looks back at his political affiliation as akin to being infected with a disease. Trotskyism has never assumed power in any country – outside the eclectic collection of Sri Lanka, Vietnam and Bolivia, it has never really won mass support – but it did provide the intellectual training ground for a surprising number of rightwingers.

In the United States, neoconservatism – a brand of rightwingery that Hitchens passionately rejects but with which his brother, the fellow ex-Trotskyist Christopher, flirted – was developed by many ex-Trots. Some of them were “red-diaper babies”, those born to leftists who had often fled to the US from tyranny.

One such was Irving Kristol, perhaps the intellectual founder of the neocons, who defined his movement as liberals who had “been mugged by reality”. Others were followers of Max Shachtman, who dramatically shifted to the right. Some were Democrats who felt they had not left the left, but rather the left had abandoned them: Jeane Kirkpatrick was a US socialist who ended up as Ronald Reagan’s ambassador to the UN and an apologist for pro-American dictatorships. Then there was James Burnham, a revolutionary associate of Leon Trotsky’s, who became a conservative writer and was awarded the presidential medal of freedom by Reagan.

There are countless examples in Britain too. Alan Milburn helped found New Labour, and now champions private healthcare firms: back in the day, he was a Trotskyist activist at a radical bookshop called Days of Hope (better known as Haze of Dope, for reasons you can probably guess). Peter Mandelson, prince of darkness, fan of Putin and champion of big business, was once in the Young Communist League.

The Tory MP Eric Pickles is known for hammering local authorities – disproportionately in poorer areas – but he was once a communist too. There are softer examples: Melanie Phillips might now think Obama is closely linked “to people with a history of thuggish, far-left, black power, Jew-bashing, west-hating politics”, but she was once the liberal-left social services correspondent of this newspaper.

It is often put to me that this is my inevitable trajectory. The leftist naivety of my earlier years will ultimately give way to hardened, real-world rightwingery, so the story goes. Those who leave the left are often those who end up detesting it more: becoming a convert often means being more zealous than existing believers.

It is held that the one thing that remains constant is the fanaticism, even if the specific beliefs are subject to change. This mischievous prediction on the right is often matched on the left. Aware of the precedents I list above, the left is often suspicious of those tiny few with a mainstream platform. It can be seen as a sign of careerism and self-aggrandisement: any political disagreement evidence of bad faith.

Swimming against the tide is exhausting. If you acquiesce, you are lauded as ‘mature’

Some on the free-market right were ideologically committed long before it was fashionable, and can claim to be pioneers. Others hailed from the left and shifted rightwards to varying degrees. You can see how this trajectory can happen. For the first few decades after the second world war, it seemed as though the left was on the advance. Back then it was the ardent supporters of the free market who were the fringe elements apparently damned by the onward march of history. Since the late 1970s, that process has reversed.

Swimming against a strong tide is exhausting. Life is easier if you acquiesce: you are lauded as “grownup”, “mature”, “nuanced”. If you reject the status quo and work in the mainstream media or politics, you are inevitably mocked. Yes, there is currently growing discontent with the free-market order across the western world, that occasionally bubbles to the surface; but any advances are uneven, subject to reverses or at risk of being swatted like insects by global capitalism.

To remain rooted in a movement and the struggles and campaigns of people fighting for social justice is probably the best insurance policy. To join others who dissent from the status quo would also help, breaking our isolation. The political winds will one day undoubtedly shift, and what now seems radical will become mainstream. Let’s hope so, anyway. Otherwise the left is just training up the rightwing firebrands of the future. A frightening thought.