ROBIN COOK has spent so much of his career in a state of pique that he must have often fantasised about how he would resign from the Cabinet.

When night was at its darkest it was unimaginable he would be able to quit with such destructive force on a matter of high moral principle as to earn a standing ovation from Labour backbenchers.

Yesterday’s events were carefully choreographed to demonstrate that this was a dignified, rational man leaving office, as he said, “with a heavy heart”, more in sorrow than in anger.

His friends yesterday pointed out Mr Cook was not a “hotheaded type” like Michael Heseltine who flounced out of the Cabinet and down Whitehall in front of the cameras in 1986. More pertinently, they also mentioned Clare Short, who last week raged over the airwaves with threats to resign before pausing to think.

Instead, Mr Cook crisply told Tony Blair on Friday that failure to secure a fresh United Nations mandate for war in Iraq would make his departure inevitable. His ministerial diary for yesterday was efficiently cleared in advance.

He then allowed himself to be photographed only on a contemplative walk with the dogs before slipping — unseen — in and out of Downing Street’s back entrance to say his piece to the Prime Minister. Their exchange of letters had been agreed in advance. Everything was as amicable as possible.

Until his personal statement to the Commons last night. As a last act of loyalty he spoke last night, rather than today, and began with praise for Mr Blair’s efforts to secure UN backing. Then he began to wield his scalpel. History will be “astonished at the diplomatic miscalculation” which led to the collapse of international coalition on Afghanistan.

“Britain is going out on a limb” for a military adventure, whch would have been unnecessary if President Bush had not won power by virtue of “hanging chads in Florida”. Our relations with Europe are now one of the casualties of a “war in which a shot has yet to be fired”.

Mr Cook’s career could have come to a messy and far less heroic end six years ago. In a VIP suite at Heathrow he was told by Alastair Campbell to make a “choice of clarity” between his wife and his lover. The then Foreign Secretary divorced his wife but stumbled on through successive controversies about his “ethical foreign policy” which led him at least once to threaten resignation. Mr Cook stabilised his position and became the “Blairite who means it”, seeking to push the Prime Minister into support for electoral reform and the euro. The former peace campaigner led the charge in Kosovo. In return, Downing Street promised him his job would be safe after the 2001 election.

It was not. For 90 minutes in June 2001 he considered quitting before finally accepting a demotion to the post of Leader of the Commons. Since then this proud, prickly man has felt further humiliated over the Government’s attempts to fix the chairmanships of Commons committees and block the modernisation of parliamentary hours. Last month his hopes of securing an elected House of Lords were wrecked by Labour MPs acting with the full authority of Mr Blair, prompting fresh speculation he would resign.

The game was nearing its end: Mr Cook had taken on Downing Street and lost. He was known to be uneasy over Iraq but colleagues said he would never forgo the official home and extra £70,000 a year that goes with his job. A senior No 10 aide told The Times recently: “The only person agonising about Robin’s position is Robin. We don’t care.”

There were suggestions last night Mr Cook may now seek a job in Europe, or more likely as chairman of the British Horseracing Board — he is a keen racegoer — when Peter Savill steps down next summer. But many MPs believe he is far from finished. He toyed with the idea of standing for the Labour leadership in 1994.

He became known as one of the giants of the Shadow Cabinet following his devastating performance in the debate over the Scott Report into the arms for Iraq affair.

Should Mr Blair be forced out — irony of ironies — over Iraq, Mr Cook even at the age of 57 may not have entirely given up on such ambition. He has a long feud with Gordon Brown going back to university days and would relish hindering the Chancellor’s succession.

Such friction has characterised his 20 years on Labour’s front bench. Although his intellect is respected, he is seen as arrogant and aloof. He recoils from making the alliances which are second nature to most politicians.

Yet in recent months he has begun building a following on the Labour back benches with young, modernising MPs over constitutional reform and such uncharacteristic attempts to make friends suggest that he has been preparing for this moment.

His resignation yesterday was not that of someone retiring from the political front line, but that of one climbing out of the trenches and crossing it.

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