He had a busy day, having emerged from his Notting Hill Gate home to be confronted by the Evening Standard, which noted that he was "dabbling blood from several fresh shaving cuts"; on to the Today programme where he dismissed as "ridiculous" suggestions that his rebellion was motivated by vengeance; and fitting in, as a pillar of the lucrative high-prestige lecture circuit, one engagement at the Academia Italiana and another with businessmen at a lunch meeting at Claridges - talking about Europe, of course.
Having flouted the cardinal rule of Commons party discipline by voting for a Labour Opposition Day motion, he left several backbenchers with the clear impression that he actually feels liberation rather than remorse at the act of political sabotage which has unleashed such abuse against him. There were only two questions that seemed to matter in Westminster yesterday: why did he do it and where does it leave him?
Mr Lamont's decision to cross his Rubicon on Wednesday night, if not exactly impulsive, was not premeditated either. He was infuriated by Douglas Hurd's magisterial mockery of him when he intervened during the winding up speech. For the second time in the day Mr Lamont had pressed the lethal question of whether he agreed with Kenneth Clarke that you could have monetary union without political union or with Lord Lawson that you could not.
Mr Hurd's reply could scarcely have been a more pointed reminder that it was Mr Lamont himself who had with John Major negotiated the very opt- out at Maastricht on which the government policy of postponing a decision on a single currency now depends: "My Right Honourable Friend is one of the greatest experts on the subject because with... the Prime Minister he negotiated the opt-out. I have always admired the skill with which they both did that. I was sitting in another room at the time."
Mr Lamont saw red. He had, according to friends been thinking of voting with the Government, however reluctantly, up to that point. Never mind that it was hardly a question either Mr Hurd or Mr Major could have answered directly without catastrophically reopening the Cabinet split. Those 45 words appeared to have changed his mind.
But it is not the first slight that had irritated the former Chancellor. In the debate on Theresa Gorman's referendum Bill last Friday, Tony Baldry, a junior Foreign Office minister had mocked contemptuously as a "bogy" the idea "that there is a conspiracy of conniving continentals seeking to rob us of our birthright..." and the "bogus" suggestion "that Britain could turn her back on Europe and abandon it".
Mr Lamont noted correctly that these were both deliberate echoes of speeches he had himself made. And this is the rub. Whether or not he is impelled by motives of vengeance (and many MPs believe he is) against the Prime Minister, whose leadership campaign he led, and who eventually removed him from the Treasury, Mr Lamont believes that in a series of speeches - including the momentous one last October, which for the first time floated the UK's possible withdrawal from the European Union, and a speech two weeks ago at Oxford (a city which he has wryly reminded colleagues is "the home of lost causes") - he has produced a closely-argued, intellectually coherent critique of the Government's European policy, to which ministers have responded only with derision or abuse.
And on the argument that he himself is one of those responsible because of his key presence at Maastricht, he tells colleagues: "The Maastricht treaty was two years ago. The opt-out was to help us make up our minds. And now I've made up my mind."
The conventional wisdom expressed by party loyalists is that his rebellion on Wednesday night has spelt the end of his career. He will lose his Kingston seat under boundary changes, and he faces an uphill struggle and some stiff competition, to find a Tory seat. But there are others, particularly some of the younger Euro-sceptic MPs - the "children of Thatcher"- who are not so sure.
Asked yesterday about his future he would only quote, with an enigmatic and faintly menacing smile, one of Lloyd George's favourite verses from the Book of Job: "There is a path which no fowl knoweth and the eye of the vulture cannot behold."
By 8am yesterday Mr Lamont was back on the lecture circuit only hours after his momentous parliamentary rebellion talking to the Academia Italiana - about Europe.Reuse content