Boris and the blunders in the war on knives

Of course Ray Lewis, the deputy mayor for young people, had to go. And let there be no doubt: this is a bad blow for Boris. After a whole election campaign, plus weeks of post-election whingeing, in which his enemies entirely missed the point about him, the Mayor has now kindly given them a big illuminated sign towards what was always his real area of weakness: detail and grip.

It will now be open season on all Boris's other appointees. Let us hope that none of them has ever had a parking ticket. A hole has been blown in the Mayor's crime policy, his most critical area.

The orgy of gloating on the Left may, however, be premature. The Westminster village is giving Lewis, and Boris, a kicking. But if the immediate reaction from radio phone-ins is any guide at all, there could be a backlash in voter-land. Ordinary Londoners may see Lewis as a man trying to save young lives, brought down by petty enmities and long-ago mistakes.

That view may not survive if further and more serious particulars surface about Lewis. It's certainly possible they could. But three days' papers have been and gone; and so far we've heard nothing of any supposed sexual misbehaviour or child abuse. So far, Lewis has not been accused of anything specific that should necessarily have disqualified him from his job - if only he had been open about it.

It's bad that Lewis does appear to have, shall we say, abuse of trust issues from the mid-1990s. But some of the most effective workers with tough kids have far worse pasts than that. The fact that Lewis comes from the same chequered background as the knife-carriers is why he can reach them in a way that middle-class social workers cannot.

We must not close public life to the mavericks, the rough diamonds, to anyone who has ever done anything unsafe. As Hazel Blears pipes her glee at the Tories' "disarray," she usefully reminds us about the risk of a City Hall entirely staffed by 10,000 copies of Hazel Blears. Ray Lewis rightly challenged the failure of the state; the forces of state failure were never going to take kindly to that.

Yet for a crusader, Lewis left himself absurdly open to attack. In politics, the kind of CV-embellishment you can get away with as a voluntary worker just won't do. It was utterly stupid to face the cameras and bluff. Did he imagine journalists would not check what he said?

Lewis might still be in place had City Hall found out about his past, pre-emptively made it public and perhaps given him a more armslength job. He, Boris, and the knife victims of London were let down by grossly inadequate staff work that failed to probe, failed to make Lewis understand the new world he was in and, worst of all, allowed Johnson to defend his deputy at a press conference without forensically examining his story to make sure it was true.

Is there any silver lining? Well, I know Lee Jasper, and Ray Lewis is no Lee Jasper. No public money is missing. No wrongdoing happened on the Mayor's watch. Unlike Ken, Boris acted quickly to lance the boil. Boris's mistake was a willingness to believe, not a willingness to deceive; his administration is still young enough to have public goodwill. Labour can usually be relied on to trump any Tory disarray with disarray-cubed of its own. And the very urgency of the knife crime problem puts all the politics into perspective.

As schools start issuing teachers with stabproof vests, Boris needs to get back to the story Londoners really care about, the blood on our streets. That, rather than this " scandal", is how he will be judged. And after rather more homework this time, he needs another policy, or person, who can recover that lost Ray of hope.