RED alert at Conservative Central Office: Eric Pickles, the bullish Tory party chairman, has outed himself as a former communist.

Pickles has revealed for the first time his passion for Leon Trotsky and Karl Marx as a teenager growing up in Yorkshire in the 1960s. He admits that he switched to the Tories only in protest at the Soviet Union’s invasion of Czechoslovakia.

“I was massively inclined that way,” says Pickles in a radio interview to be broadcast tomorrow. “It was part of my upbringing.

“I was a pretty serious young chap. For my 14th birthday I got Trotsky’s History of the Russian Revolution as a present — and I read the damn thing.”

During his youth in Keighley, Pickles also read the Communist Manifesto and Das Kapital, and even compiled an admiring school project on Marx.

In the Radio 4 documentary, The ’89 Generation, leading MPs discuss the impact of the fall of the Berlin Wall on their political beliefs.

Michael Gove, the shadow schools secretary, also reveals a radical streak. He was on a workplace picket line when the Wall came down.

Pickles’s flirtation with communism is not mentioned on the official Conservative website; nor is it raised on his own Wikipedia entry, although the site does mention that his great-grandfather was a founder of the Independent Labour party.

The MP for Brentwood and Ongar tells the presenter Anne McElvoy that it was Moscow’s violent response to the Prague Spring, the liberal reforms introduced by Alexander Dubcek, the Czech leader, that drove him into the Tory fold.

“I was 16 years old in 1968 when Dubcek’s Spring was crushed. I was very interested in Dubcek and thought it was the natural evolution of communism. So I felt a tremendous shock when the tanks rolled into Prague.

“I thought the [inaction from the] British government [of the Labour prime minister Harold Wilson] was useless, in the way that only a 16-year-old can think the British government is useless. And I thought: ‘What’s the most outrageous thing I can do to protest? I know, I’ll join the Conservative party’.”

Pickles, 57, who discouraged colleagues from drinking champagne at this year’s Tory conference, says he did not initially intend to remain a Conservative but found himself naturally moving towards the right.

The MP, who is often deployed as an attack dog against the government, also confesses to shedding a tear when the Berlin Wall finally fell in 1989 — as do Nick Clegg, the Liberal Democrat leader, and Gisela Stuart, the German-born Labour MP.

Asked later if there was any danger of a left-wing relapse, Pickles guffawed: “That would shock them, wouldn’t it? After doing 40 years in the Conservative party, I think I’ll stay.”

Militancy also played a brief role in the career of another Cameron loyalist. Gove, a former journalist, reveals in the programme that he was on the picket line in a regional newspaper dispute when the Wall fell. The documentary unearths a clip of “Red Gove” berating the management of a local newspaper for reneging on its workplace promises.

“I was warming my toes ... by the brazier as I joined my colleagues in demanding the right to be represented by a trade union,” he says. “I was also a member of the Aberdeen South Young Conservatives — which caused no end of ribaldry.”

In the clip, the young Gove intones: “Management are denying people the chance to be governed by a collective bargaining deal and denying freedom of choice in the workplace.”

The fall of the Berlin Wall divided the Conservatives in power over how to deal with the aftermath. David Willetts, the shadow universities secretary, says Margaret Thatcher, then prime minister, was wrong to oppose German unification at the time.

One long-lasting impact of the Wall’s demise was a wave of immigration from eastern Europe, an issue seized by William Hague after he became Tory leader.

But Hague, now shadow foreign secretary, tells McElvoy, a columnist for the Evening Standard newspaper, that he regrets his controversial claim in 2001 that Britain was turning into “a foreign land”. He admits: “Partly we didn’t get it right and partly it was easily misrepresented.

“Talking about a country that’s going to change into something you don’t want was easily misrepresented as saying we were being overrun by foreigners. That was our fault.”

His policy on asylum was prescient, but the tone and wording were mistaken, he says. “I regret it among hundreds of things I did when I was leader of the Conservative party.”

Anne McElvoy presents The ’89 Generation at 11am tomorrow on BBC Radio 4