Sir Ludovic, whose investigative work into miscarriages of justices is credited with speeding up Britain’s abolition of the death penalty, passed away in a Salisbury nursing home on Sunday.
His varied career saw him as a naval officer in the Second World War, a BBC presenter, a campaigner for euthanasia, atheism and Scottish independence, and a prolific writer of books and newspaper article.
His book, Ten Rillington Place, helped to win Welshman Timothy Evans a posthumous pardon after he was hanged for the murder of his baby in 1950.
Sir Ludovic pinned the blame on serial killer John Christie and the popularity of the book helped sway public opinion against the death penalty, leading to its abolition in 1969.
Richard Ingrams, co-founder of satirical magazine Private Eye, told the BBC that 10 Rillington Place "exposed the fact that the British judicial system could get things hopelessly wrong and would then try to cover them up".
He said, despite Sir Ludovic’s connections with the Liberal party and his "very impeccable Establishment background", he was really "a bit of an anarchist".
"For somebody like that to be engaged in the exposure of miscarriages of justice -- it gave him an advantage," he said. "He couldn’t be dismissed as a left-wing lunatic or anything like that."
Edinburgh-born Sir Ludovic twice failed to become a Liberal Democrat MP, but Nick Clegg, the present LibDem leader, yesterday hailed him as a man the party was proud to call one of their own.
He said: "Ludovic Kennedy was one of the great thinkers of his generation. His pursuit of justice and championing of sometimes unpopular and controversial causes marked him out as a true liberal.
"He will be greatly missed."
Sir Ludovic resigned from the Liberal Democrat Party in 2001 because of what he said was the incompatibility of his fiercely held pro-voluntary euthanasia views with those of the then leader Charles Kennedy, a Roman Catholic.
Sarah Wooton, chief executive of Dignity in Dying, paid tribute to his activism: "We are saddened to hear of the death of Sir Ludovic Kennedy.
"He was a passionate advocate of assisted dying for terminally ill people, whose compassion and vigorous intellect were an asset to the organisation," she said.
"As a former president, he helped to lay the foundation for the recent successes of the campaign, with the director of public prosecutions now formally recognising a difference between compassionate and malicious behaviour."
In the 2001 General Election, Sir Ludovic stood as an independent candidate, on the platform of legalising voluntary euthanasia, for the Wiltshire constituency of Devizes.
He won 2% of the vote and subsequently rejoined the LibDems but, according to fellow activist Diane Munday, he never lost his fire for the issue.
"He was humane, sympathetic and influential man," she said.
"Even when reliant on sticks for support in his last few years, he would make enormous physical efforts to attend pro-assisted euthanasia meetings."
Sir Ludovic was also a life-long atheist and wrote All In The Mind: A Farewell To God in 1999, in which he discussed his philosophical objections to religion, and the ills he felt had come from Christianity.
Hanne Stinson, chief executive of the British Humanist Association, said: "Sir Ludovic was a stalwart supporter of the BHA and a progressive campaigner on many fronts. He will be sorely missed."
Sir Ludovic had been frail for some time after catching pneumonia after a fall last year.