So farewell then Dhiren Barot, sentenced at the down-at-heel Woolwich Crown Court to a minimum of 40 years for planning a series of spectacular terrorist attacks, including one to blow up a tube train under the Thames (somewhat surreally headlined “Plot to blow up River!” by the Evening Standard) and another called the “gas limos” project – to drive limousines filled with gas bottles into prominent public buildings.

Mind you, Barot never got close to enacting these schemes but nor did they stay at the pub bollocks stage either. Barot had developed detailed plans and costings for the projects – they were written in the pro forma manner provided by Small Business for Dummies type books, he’d met with al-Qaeda links overseas, and he’d developed a complex routine of coded messages which the plod are yet to crack (though possibly an intelligent 11-year-old could).

So it was a serious threat, and – unlike some on the left – I don’t regard these things as simply beat-ups. There are clearly a small but real number of people in the UK and elsewhere out to create mayhem.

But 40 years for schemes that never got close to buying explosives, or an actual attempt is pretty draconian. It turns on its head the legal principle that you get punished not for what you intended to do, but for what you actually did (hence the difference between attempted murder and murder charges and penalties). Judging from the evidence provided, Barot was nowhere near as advanced as the 9/11 bombers.

40 years is disturbing not merely because of a pure distortion of that sentencing principle, but also because it may also lessen the deterrent effect of differing sentences. If you’re going to get forty years for planning an attack and scouting out the terrain, why would you hesitate to go through with it?

Every would-be bomber – and it would be silly to overrate the resolve of each and every one, though Barot seemed pretty stalwart – now knows that there is absolutely nothing to lose by taking it to the limit. How could you possibly accord a more successful attack an appropriate punishment.

As a regular Tube user, I won’t shed any tears for Barot. But nor do I want liberal society destroyed in order to save it.