So the bombers in this case had adequately safe main charges, and in those pre-liquids-ban days they could have taken quite big ones onto the plane with them. They also had viable detonators, safe enough for suicide terrorists to use if not for normal explosives folk, well able to give the main charges the high-velocity shock they would need to make them detonate rather than deflagrate or burn. All they needed to do in the airliner loos was hook up their dets to the firing circuit, open the bottles, slip the dets in and press the button. Job done.

It's the possession and use of detonators, indeed, that's the hallmark of a serious bomber. The Provisional IRA (PIRA) of old used detonators, both proper manufactured ones and homemade. These were very often the primaries for highly effective home-made charges, which went off quite reliably and caused a lot of destruction. The bombers in this case were serious - not by any means in PIRA's league yet, but getting there - and their plan was a good one. The prosecutors have failed to prove to the jury's satisfaction that the devices were aimed at airliners, but nobody - not even the three convicted bombmakers themselves - suggests that the bombs weren't viable, or that they couldn't have got through security.

There's nothing intrinsically impossible about home-brewing effective bombs out of fairly everyday stuff, remember - other people than PIRA were bound to get wise eventually. And let's be quite clear: acknowledging this reality is not the same as endorsing lengthy detention without charge. It's not the same as saying that battlefield chemical warheads are equivalent to nukes; it's not an argument in support of massive state snooping powers, the use of or connivance at torture, airstrikes against children etc. It's perfectly possible to argue that terrorist bombings aren't, in fact, a significant threat to western society and yet acknowledge that this particular plan was a feasible and dangerous one.

Does the liquids limit prevent this kind of attack? No, not really. It's fairly easy to get round, in fact; a big team of terrorists with boarding passes for many different flights could bring many small amounts of liquid main-charge through security and combine them afterwards, still needing only one detonator, one firing device and one suicide bomber.

But there are no big teams of terrorists in the UK. MI5 says that the average size of a UK terror cell known to them is ten. As a general rule, as soon as you have more than, say, five people in your UK-based jihadi cell, you have probably popped up on the security services' radar in some way - quite likely because you have an informer in your midst. So perhaps the liquid limits are worthwhile, the more so as everyone has now got used to them and the worst of the inconvenience has died down. Personally, I'd still happily fly without them; but I'd never die in a ditch to get rid of them either. Permission to take liquids on planes is scarcely the most important freedom that has lately been taken away from us.

Were the jury idiots, not to send the three bombmakers down on the big airliner charge? Should they have convicted the other four, who had made "martyr" videos but couldn't be positively tied to the bomb factory - the four suicide mules who would have carried the devices, according to the prosecution?

It's only one man's opinion - worth what you paid for it, eg nothing really - but I say no. The bombmakers have been convicted of being bombmakers - they'll go to prison for a long time. The video idiots will do less time, presumably not very much more than they already have awaiting trial. But all of them will be watched for the rest of their lives; their usefulness as terrorists is over. They are out of play, and as for encouraging les autres, forget it - you don't deter suicide bombers by custodial sentences (or even death sentences).

And the numbers probably will stay small; the more so, following these verdicts. The message is clear - the British courts are fair, or anyway their juries are. You will be given the benefit of the doubt in a jury trial, even if you are a dark-skinned bearded man with a scary name; even if you have made suicide videos and you admit up front that it was your plan to let off high explosives in a crowded public place. If the prosecutors can't prove beyond reasonable doubt that you were also going to blow up a plane, you still won't be convicted of trying to.

Frankly, if I was the Home Secretary I'd be making a massive propaganda coup out of this - not thinking about wasting a shipload of taxpayers' money on a retrial. (That would be expensive. Lawyers and judges are paid a lot more than either prison guards or surveillance teams, and you'd still need screws and spooks afterwards even if the retrial was "successful".)

It seems that the British security services are pointing the finger at America over the failure to make the airliner charges stick. It's being said that US-inspired haste at the Pakistani end of the operation meant the UK cops had to move too soon, before the bombers had even bought their airline tickets. Everyone's moaning about the pesky Americans going off half-cocked.

But what's the aim of the game here? Is it victory to get a longer jail sentence for a terrorist? One might argue that once you're talking about jail you're talking about damage limitation after a defeat, not victory of any kind.

Victory, you might say, is when a young man meets a Taliban or al-Q recruiter - travelling in Pakistan, at the mosque back home, at university, wherever - and finds himself unconvinced. That sort of genuine and elegant victory, you could argue, is more likely following this week's results - not less.

And it just could be that this time the hasty Americans in Pakistan, triggering an early end to the UK surveillance operation, have actually done us a favour. Possibly the accused men were planning mass murder, as the prosecution contends: but the cause of Western democracy gains a lot more by showing the world the manifold excellences of trial by jury than it could ever lose by failing to make that charge stick. ®

Lewis Page used to be a mine clearance diving officer in the Royal Navy. As such, he was trained in demolitions and bomb disposal. He was assigned as a bomb-squad operator in support of the mainland police from 2001-2004, holding a UK improvised-devices disposal licence for that period.