A few months ago, Tam Dalyell, the veteran Labour MP and founder of Parliament's awkward squad, said Tony Blair was the "worst Prime Minister" of the eight he has known.
Over afternoon tea with strawberry jam and scones in the elegant Pugin Bar at the House of Commons, Mr Dalyell confided to me that he had changed his opinion of Mr Blair.
Mr Dalyell, 71, announced last week that he would retire at the next election after more than 40 years at Westminster. Mr Blair, perhaps thankful that his adversary was quitting, led the tributes to him. "Fiercely independent, Tam's persistence in pursuing causes close to his heart is legendary," Mr Blair told the House.
The kind remarks by the Prime Minister cut little ice with the member for Linlithgow who, as the longest-serving MP, is also Father of the House. After decades of outspokenly opposing British military interventions, from Suez to Iraq, and leading campaigns on the environment, international relations and civil liberties, he has no intention of leaving quietly.
"Tony should go," he declared. "And he should take his friend Lord Falconer [the Lord Chancellor] with him."
Mr Dalyell believes that Mr Blair has all but destroyed Cabinet government with his "presidential" style and that he is too remote from his party. "He has talented people in his Cabinet but they don't have power bases in the party," he complained.
"I am incandescent with anger with him. We had far more understanding from Harold Wilson, Jim Callaghan, Ted Heath, Alec Douglas-Home, and from Harold Macmillan and John Major.
"Even Margaret Thatcher - whatever I have said about her role in the Falklands War - acted because we were attacked. In the war on Iraq we adopted a new doctrine of the pre-emptive strike. It is a disastrous doctrine."
His rebelliousness has included his hounding of Lady Thatcher over the sinking of the Belgrano, the Argentinian cruiser, as well as opposition to the 1990-91 Gulf war and the Kosovo campaign. Mr Blair once claimed that he had opposed "every bullet fired since 1945".
Because he has so often rebelled, many people believe that he is a Leftist, and for a period he was indeed a member of the hard-Left Campaign group, albeit its only member who regularly wears an old Etonian tie.
In truth, though, he is hard to pigeon-hole. The best description of him would be as an immensely courteous, eccentric toff: Sir Tam Dalyell Bt, a hereditary baronet, whose home is his family's turreted 17th century mansion, The Binns, at Linlithgow. Rather like the ravens at the Tower of London, it is said that while peacocks parade on the lawns of The Binns (Gaelic for hills) it will remain in Dalyell hands.
Unlike many on the hard-Left, he is a pro-European, a believer in nuclear power and a fierce opponent of devolution, even for his native Scotland. He once boasted: "I'm ancient Labour. I want nothing from the party leadership, so they cannot control me."
He tried to exculpate Col Gaddafi over the Lockerbie atrocity and last year sparked outrage by accusing the Prime Minister of being unduly influenced by "a cabal of Jewish advisers".