Definitely an early-use weapon, Prime Suspect 3. A guaranteed ratings grabber, yes, but the subject matter - paedophile rings, transvestitism, child abuse and torture - doesn't quite meet the seasonal requirement for artificial glee. Any closer to Christmas and they would have looked like party-poopers. Besides, it was clear by the second hour that this was one of those heavy pieces of machinery which you shouldn't operate after taking Benylin expectorant - or one too many glasses of advocaat.
Part of the pleasure of the first Prime Suspect was the purity of its plot - we know he did it but can we prove it? That single face-off, between calculating killer and determined detective, offered a tow- rope whenever the fascinating procedural details threatened to bog you down. In Prime Suspect 3, on the other hand, it was all you could do to keep up with the cast list, a problem not helped by the fact that half the characters had women's names as well as men's. Even the policemen dragged up at one point trying to infiltrate a transvestite night-club.
Add to that a paedophile conspiracy that involved the upper echelons of the police and a list of suspects as long as a new- style truncheon and the result was a film which left you feeling like a slightly dim Hendon cadet on work-experience. When you weren't catching up you were wasting time on wild fancies. The fact that three very different characters all used the phrase 'I swear before God' at moments of pressure had me constructing an elegant theory about secret evangelical connections, but, as it turned out, a lazy script-editor was in the frame for that one.
Whoever he or she is, they ought to ask for some other offences to be taken into consideration when they go for sentencing - 'You've a very promising career - don't blow it', for example.
The politics are getting a little programmatic too. Having dealt with gender and racial prejudice in the first two films it was the turn of gay policeman to have their plight illuminated last night. Watch out for the disabled seal in Prime Suspect 4.
This is a little churlish. Mirren is wonderful - capable of recharging a line with a little jerk of the head - and La Plante's script displayed, as always, a remarkable peripheral vision - you learnt more than you really wanted to know about the scientific details of death by fire and one nice scene swung on the complicated career- jockeying that the threat of the Sheehy report had started in the force. La Plante also makes sure that you can't just watch all this as a cerebral entertainment - the repercussions of the crimes ripple out beyond the immediate victims, touching the careless and the innocent as well.
But television audiences are fickle creatures and we can afford to be churlish now in a way we couldn't when the first Prime Suspect was transmitted to a grateful nation. If you want a dark take on police politics you can get it from Between the Lines (BBC 1). If you want an unblinking vision of the nastiness of crime, Cracker (ITV) has opened for business too. If you want the mental close combat of the interview room, Homicide (C 4) offers a good transatlantic version.
In a couple of cases here, I suspect La Plante showed the way and she deserves the benefit of the doubt for that, but
doubt didn't enter into it with the first Prime Suspect.