The left-wing radical, who renounced his peerage to become the longest-serving Labour MP in history, has died at the age of 88.
Benn sat as a Labour MP over six decades and held ministerial office several times before moving to the far left of the party.
He was an outspoken opponent of military action in Afghanistan and Iraq, and he topped several polls of the most popular politicians in the country.
Born Anthony Wedgwood Benn, he was first elected to the House of Commons in 1950 but was forced to step down a decade later after inheriting his father’s title and becoming Viscount Stansgate.
Peers were barred from sitting in the Commons, but Benn campaigned to change the law.
The peerage act of 1963 allowed the renunciation of peerages, and Benn became the first peer to give up his title. He returned to the Commons after winning a by-election the same year.
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By the early 1970s double-barrelled Anthony Wedgwood Benn was going by the name Tony Benn. He later tried to remove references to his private education at Westminster School from Who’s Who.
Benn held several cabinet posts in the 1970s, including secretary of state for industry and secretary of state for energy under Harold Wilson and Jim Callaghan.
He stood unsuccessfully for the Labour leadership in 1976 and 1988.
By the end of the 1970s Benn had become of the most influential figures on the far left of the Labour party.
Benn variously advocated the abolition of the House of Lords, the unification of Ireland and the end of the monarchy.
Despite serving as an RAF pilot in world war two, he was a frequent opponent of military action, opposing the Falklands war, the Kosovo war and the invasion of Iraq and Afghanistan.
He later said Tony Blair was guilty of “a war crime” for misleading the House of Commons over the justification for the invasion of Iraq.
Benn became president of the Stop the War Coalition after his retirement from politics in 2001.
In a 2007 BBC poll Benn was voted the UK’s Political Hero, after winning 38 per cent of the vote, beating Margaret Thatcher with 35 per cent.
Labour leader Ed Miliband led tributes to Mr Benn from across the political spectrum.
Mr Miliband said: “For someone of such strong views, often at odds with his party, he won respect from across the political spectrum. This was because of his unshakeable beliefs and his abiding determination that power and the powerful should be held to account.
“He believed in movements and mobilised people behind him for the causes he cared about, often unfashionable ones. In a world of politics that is often too small, he thought big about our country and our world.
“Above all, as I had cause to know, he was an incredibly kind man. I did work experience with him at the age of 16. I may have been just a teenager but he treated me as an equal. It was the nature of the man and the principle of his politics.”
Prime Minister David Cameron said: “I am sorry to hear that Tony Benn has died. He was a magnificent writer, speaker, diarist and campaigner, with a strong record of public and political service.
“There was never a dull moment listening to him, even when you disagreed with every word he said.”
Former Labour prime minister Gordon Brown said: “Tony Benn was a powerful, fearless, relentless advocate for social justice and people’s rights whose writing as well as speeches will continue to have a profound influence on generations to come.
“My thoughts are with his family, whom he adored.”
Tony Blair said: “Tony Benn was one of those rare things – a genuine radical for all his life. He was a fearless campaigner and a legendary figure for the Labour movement.
“Even when I disagreed with him, I always had enormous respect for his brilliance, his passion and his commitment to the people of Britain and of the world. My thoughts are with his family – with whom he was very close.”
Unite general secretary Len McCluskey said: “Every socialist, active trade unionist and progressive campaigner of the last 60 years or more will be bereft this morning, since their lives will have been entwined with Tony Benn’s.
“He was a hero to me and to millions more, not only because of what he advocated – social justice, democracy and peace – but because of the way he advocated it, with passion, decency and without malice against anyone.
“Tony fought for his ideals almost to the last breath of his life. He was a life-long member of Unite and the T&G before it, and I was proud that we were able to honour his life in his presence at our executive last December.
“His life is a rebuke to all those who are cynical about politics and politicians, and I hope that all today’s political leaders will pause for a moment to reflect on why Tony Benn was held in such high esteem by so many from all walks of life.”