London ? The British have learned more about their vaunted intelligence service and their determined, moralistic prime minister than they probably wanted to know. They have learned that both James Bond and Tony Blair can make mistakes.

The independent judicial inquiry ordered by Blair into the suicide of a government scientist is winding down, with the prime minister having successfully refuted allegations that he slanted intelligence reports to justify joining the invasion of Iraq. Blair’s integrity has been defended, at some cost to his humanity.

The inquiry also provides a rare glimpse of British spies at work. That too is a mixed blessing.

Spies tend to be expert liars who create an air of omnipotence and invincibility as survival tools. Exposing them as mortals who waffle, change their minds and make mistaken judgments can threaten their very existence. That is the double-edged sword on which Blair and his comrade in arms, President Bush, balance as they attempt to clear their names on Iraq without wrecking their intelligence services.

The key disputed intelligence issue here was whether Blair’s political team fabricated and inserted into a government dossier the claim that the Iraqis could deploy biological or chemical weapons in 45 minutes, as a BBC radio report alleged. The inquiry has shown that Blair and his powerful communications director at 10 Downing Street, Alastair Campbell, erupted in self-righteous anger over this monstrous accusation. After all, they knew they were innocent.

Blair is a true believer. He takes seriously his causes, his reputation and the chance he has to change Britain and the world. Other politicians would have issued a denial, rapped the news organization and moved on. But Blair opened in private and then in public a bitter argument with the BBC that ultimately damaged both his government and that proud news organization. He unleashed a lose-lose contest of wills.

The information did in fact come from the spooks, who put the Iraqi deployment time at 20 to 45 minutes. But the evidence put before the inquiry also indicates that this ominous-sounding factoid was thinly sourced and referred to specific, small-scale operations. Context was all.

Intelligence gathering is more art than science. But political leaders are reluctant to face up to or explain to their publics the reality of the inherent uncertainty of the spy agencies’ assessments. Blair and Bush were forced to making political judgments on the basis of incomplete and conflicting assessments. They should have been more candid with their publics about that.

Men of science — such as the late David Kelly, the weapons inspector who seems inadvertently to have set the BBC off on its wild dossier chase, or the laboratory experts in America who claim that Saddam Hussein could not possibly have intended to use aluminum tubes for atomic centrifuges — are accustomed to dealing in black-and-white answers. Intelligence analysts most often deal in grays. They tailor their written judgments to be read in retrospect — that is, in the light of subsequent events, whatever those are.

Today it is the critics who rush furiously to ignore context. They blame Blair and Bush for “lying” because U.S. and British forces have not found the weapons of mass destruction that virtually all the intelligence services and foreign ministries of the world believed were in Iraq.

That unfruitful search enables opponents to channel misgivings about the conduct of postwar operations into retroactive attacks on the credibility of Blair and Bush. It is now suggested that the two leaders should have based life-and-death policy decisions on footnotes and obscure dissents in deliberately murky intelligence analyses. Rubbish, as they say here.

Blair is now regrouping for a fresh political start after a vicious drubbing this summer at the hands of a media that has become the main force of opposition in Britain. The long-planned but abruptly announced departure of Campbell, who served as a lightning rod for Blair in the communications job, should help clear the decks.

Blair’s inquiry has parted the thick curtain of official secrecy that shields British intelligence and other officials from the public scrutiny that Americans take for granted. This should be the beginning of a serious examination on both sides of the Atlantic of how the intelligence services have performed on Iraq.

The nature and context of that intelligence — and the operation of the agencies that produced it — need as thorough an examination as the political uses to which it was put. Political leaders must have the stomach to risk acknowledging that their James Bonds are flawed mortals who don’t always have all the answers either.