The former home secretary may be wondering today if he should not have been a little more wary of the genial giant who, as Metropolitan Police Commissioner, was his most senior policeman.
Lord Stevens may not have taken a witness to his meetings with his boss but he certainly seems to have kept careful notes for his vivid memoir, Not for the Faint-Hearted. The result, according to the first extract published in today's News of the World, is a book that includes a deeply unflattering portrait of Mr Blunkett as a deceitful bully.
Their relationship began to sour in the wake of the 9/11 attacks when the then Home Secretary questioned the police's ability to deal with the terrorist threat. Lord Stevens claims that Mr Blunkett lost little time in briefing against him when he stood up to him in front of other Cabinet ministers.
The former police chief recalls his amazement at reading accounts of a dressing down by his boss that had not occurred. Again and again, claims the former police chief, articles appeared in the press detailing their differences and portraying the Home Secretary in a flattering light.
After one such account of an argument had appeared he recalls saying to friends. "I didn't know where the story had come from. There were only three of us in that office - myself, the Home Secretary and his dog. And it didn't come from the dog."
On another occasion, Lord Stevens says he was aghast to read that his job was on the line the day after he and the Home Secretary had shared dinner at Scotland Yard. Mr Blunkett had even told him: "We stand together or go down together."
"Our worst spat came in February 2003 when he reviled me publicly for sending tanks to defend Heathrow on the grounds that their appearance would terrify the public. In fact, the vehicles were light armoured cars, not tanks, and it was David Veness, then head of the Met's Specialist Operations Branch, who had ordered their deployment. Later Blunkett claimed I had been devious in saying the 'tanks' were only armoured cars - but this true remark been made not by me, but by David."
Another source of tension was police reforms begun by Jack Straw but aggressively stepped up by Mr Blunkett - against the advice of the then Met Police chief that it would "end in tears".
"My forecast proved correct when 14,000 police officers marched on Parliament."
Eventually tired of the attacks on him, Lord Stevens says he was forced to let Mr Blunkett know, through political go-betweens, that he was ready to fight back.
"When he continued to run me down, I rang two friends close to very senior figures in Government and told them I wasn't going to stand for it. If it went on I was going to come out fighting. Lo and behold, the insults ceased - and indeed there came a complete change of attitude."
In his book Lord Stevens also reveals new details about a terrorist plot to assassinate Tony Blair during the Queen's Golden Jubilee Parade. He is fulsome in his praise for Mr Blair's response when he told him that there was a direct threat to his life.
"To his credit, he immediately said he put duty before his personal safety and that he intended to take part in the ceremonies as planned. Cherie was equally resolute. Mr Blair remained very calm and very pragmatic." Both the Prime Minister and his wife refused to wear bullet-proof vests. "I have nothing but admiration for the way they handled what would have been extremely frightening."
In the event the procession passed off without incident but Lord Stevens believes that it was one of eight terrorist plots foiled during his period as Met Commissioner.
He says his prediction that the July 7 bombers were British drew "cries of protest" but proved correct. "We believed up to 3,000 British born or British based people had passed through Osama bin Laden's training camps and we suspected that some of them had returned home to become Islamic terrorists."
Despite his praise for Mr Blair, the former Met chief was never regarded as a political friend of New Labour, preferring to preserve his independence. His successor, Sir Ian Blair, has been notably more accommodating.Reuse content