For all that, and on strictly practical grounds, I do wonder whether prison is the right place for him. All I can think of, contemplating Abu Hamza's arrival at HMP Belmarsh or wherever, is the beatific grin on the face of the screw in charge of the jail's dramatic society. For ages, this officer has doubtless been dying to put on Peter Panf and year after year, the requisition form for the hook has come back from the governor's office stamped 'Rejected'. And now, would you believe this stroke of luckf here's Hooky, exquisitely well cast by nature and that accident "clearing land mines" in Afghanistan, and ready to roll, no props required.

This, in a facetious nutshell, is my problem with the imprisonment of Hamza.

Whatever he has said and done to promote and propagate violence, it remains difficult to see him as anything more serious than an overblown parody of the pantomime baddy. His given name on being born in Alexandria, Mustafa Kamel Mustafa, doesn't help. I've a vague feeling that Mustafa Kamel was a punchline from that gritty 1968 exploration of guerrilla warfare in Afghanistan, Carry On Up the Khyber.

Anyway, you can see why he changed his name on coming to Britain and taking up an early spiritual appointment as a nightclub bouncer in Soho. No one wants a comedy name, least of all if he hopes one day to become an important religious figure, and as Sheikh Abu Hamza of the Finsbury Park mosque he somehow contrived to become just that.

Whether he was ever quite the danger he is now considered to have been is another matter. The really grave threat to public safety from Islamic terrorists, so we've continually been told these last four years, is posed by sleepersf those cunning, silent, patient types who embed themselves in society so deeply and respectably that no one has a notion of the murderous intent in their hearts.

They might be the earnest accountant or the friendly dentist, the GP or the social worker. They might even be a cuddly classroom assistant, like Mohammad Sidique Khan, the brains behind the 7 July bombings.

The loving father of a baby daughter, Khan was a 'teaching mentor' to the children of immigrant families in Leeds, and his colleagues at Hillside Primary described him as immensely popular with the children, who referred to him as their buddy. On this evidence, it seems a safe bet that Khan preferred to chat about Thomas the Tank Engine with his young charges, whereas one doubts that Abu Hamza would have waited for a child to cut its first teeth before trying to brainwash it about the Zionist conspiracy and the need for holy jihad.

Khan was the very model of a sleeper. Had he been anything else . . . had he, for example, been a vocal regular at the Finsbury Park mosque . . . we are entitled to presume that the security services would have noticed him long before 7 July 2005.

We might well presume that . . . but we would be wrong, since another of the 7/7 bombers, Shehzad Tanweer, was just such a worshipper, according to a family which blames Hamza for his involvement in the plot.

This, far more than the question of why Hamza wasn't prosecuted earlier, is the mystery. How could the intelligence services have spent so many man hours and used such sophisticated surveillance techniques to watch Hamza over so many years without picking up disciples such as Tanweer?

In the history of covert intelligence, there may never have been a gift like Abu Hamza . . . such an absurd pastiche of a Western government propaganda machine's vision of an Islamist bogeyman that he might have been a hologram created by the same talent pool that came up with the 'dodgy dossier'. If you were an Alastair Campbell figure with two pressing concerns . . .

ratcheting up fear to facilitate the passing of draconian anti-terrorism legislation on the one hand;

and on the other, providing juicy gifts for your friends in the press . . . the grizzly, gruesome Hamza is precisely what you would invent.

If it is true that he incited young men to maniacal dreams of martyrdom, you'd have thought that his continued presence in the mosque, acting as the honeypot to the more lethally extremist bees, would have been priceless for the anti-terrorist agencies. In fact, I'd always assumed that Hamza was a sleeper himself, planted by the British government to flush out the likes of Tanweer and bring them to the attention of MI5. Now those minded to blow up themselves and their fellow citizens will be far more cautious about revealing their sympathies in public, and will prefer to do their plotting from anonymous internet cafes.

As a lightning rod to draw the streaks of public outrage away from the intelligence failures that allowed the atrocities of July to occur, and then so nearly recur a fortnight later, Hamza's conviction is a short-term godsend. As a distraction from worrying about the root causes of the unnatural fury felt by that small element of Muslim youth to whom he appealed, it may also be invaluable. Yet somehow I'd feel an awful lot safer if he was still at liberty, queueing next to me to pay for the family shopping in the Lebanese supermarket on the Uxbridge Road and peddling his pernicious drivel in Finsbury Park, rather than learning his lines in D-Wing for that must-see Christmas production of