Tributes poured in from all sides of politics to the veteran Labour politician and former cabinet minister Tony Benn, who has died at home at the age of 88.
Labour leader Ed Miliband described the former figurehead of the Labour left as an "iconic figure" and said the party had lost a "champion of the powerless, a great parliamentarian and a conviction politician".
Prime Minister David Cameron said that Mr Benn ensured there was "never a dull moment", even for those who disagreed with every word he said.
First elected to parliament in 1950, Mr Benn renounced a peerage in order to remain in the House of Commons and was an MP for more than 50 years, serving in the cabinets of Harold Wilson and James Callaghan and staging a bitterly divisive battle with Denis Healey for the Labour deputy leadership as the champion of the left in 1981.
He famously retired from parliament in 2001 saying he wanted to "spend more time on politics" and won a new status as a national treasure touring the country to speak to packed audiences in venues from town halls to West End theatres and the Glastonbury festival. Well into his 80s, he was a familiar and popular figure at demonstrations and anti-war rallies.
In a statement released early today, his children Stephen, Hilary, Melissa and Joshua said: "It is with great sadness that we announce that our father Tony Benn died peacefully early this morning at his home in west London surrounded by his family.
"We would like to express our heartfelt thanks to all the NHS staff and carers who have looked after him with such kindness in hospital and at home.
"We will miss above all his love which has sustained us throughout our lives. But we are comforted by the memory of his long, full and inspiring life and so proud of his devotion to helping others as he sought to change the world for the better."
Mr Miliband paid tribute to an "iconic figure of our age".
Mr Miliband said: " Tony Benn spoke his mind and spoke up for his values. Whether you agreed with him or disagreed with him, everyone knew where he stood and what he stood for.
"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.
"I saw him for the last time a couple of weeks ago in hospital. He may have been ailing in body but was as sharp as ever in mind. As I left he said to me 'well, old son. Let's have a proper talk when you have more time'."
Mr 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."
Labour's former 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."
Mr Benn was admitted to Charing Cross Hospital in London at the beginning of February after feeling unwell, and returned home on March 4.
He was born in 1925 as Anthony Wedgwood Benn into a political dynasty which included two grandfathers who sat in the Commons and a father who was first a Liberal and then a Labour MP.
The family tradition was continued by son Hilary, who is Labour's shadow communities secretary, and granddaughter Emily Benn, who stood for the party at the 2010 general election.
Benn's decision to give up the title Viscount Stansgate, which he inherited on his father's death in 1960, led to the Peerage Act of 1963, allowing the renunciation of hereditary titles.
He was seen as a modernising technocrat when he entered government, but was an unusual example of a politician who became more left-wing as he grew older, crediting the change to his experience in government of seeing progressive reforms blocked by the establishment.
He has not been forgiven by some in the Labour Party for his espousal of radical left-wing views in the 1980s, which some blamed for ushering in the creation of the breakaway Social Democratic Party and the long political ascendancy of Margaret Thatcher.
His death comes just days after the loss of a left-wing hero of a later generation, RMT union boss Bob Crow.
Labour MP Dennis Skinner, who had known and worked with Been since 1970 and campaigned alongside him during the miner's strike of 1984/85, said: "He was one of the greatest assets the Labour Party has ever had.
"He was a campaigner and a teacher. His whole idea was about trying to influence people, not just in Parliament but outside too."
The chair of the Socialist Campaign Group of MPs, John McDonnell, said: "Tony Benn was the articulate advocate of socialism who inspired my generation and gave us all hope of a fair and equal society.
"He will be remembered for his principled commitment to his socialist beliefs and his principled stand on so many issues. His passing adds to a terribly sad week for the Left, coming so soon after the loss of Bob Crow."
Former foreign secretary Dame Margaret Beckett described him as "delightful, friendly, very open-minded and interested always in new ideas".
She told BBC Radio 4's Today programme: " He had such clarity of expression, he opened people's eyes and he made them think.
"He made enemies and kept enemies but on the whole I think most people regarded him with a good degree of affection, long before he got sufficiently old - as he said himself - that he can't do any more harm."
Former Cabinet minister Peter Hain said: "Tony Benn was a giant of socialism who encouraged me to join Labour in 1977, a wonderful inspirational speaker and person who will be deeply missed."
Labour's former spin doctor Alastair Campbell tweeted: "RIP Tony Benn. A fighter all his life, fought death with the same courage he lived life. A large and loving family there with him to the end."
Former prime minister 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."
Former prime minister Sir John Major said: "Tony Benn was a true political warrior, who fought for what he believed - right up to the very end.
"Although he never led the Labour Party, he will always be remembered as a truly great parliamentarian,
"We would never share the same political philosophy, but he was a man for whom I had tremendous admiration, respect - and huge affection."
A spokesman for the Benn family s aid: "In response to a number of queries about where floral tributes to Tony Benn might be laid, they can be placed on the north side of Parliament Square."