There's nothing new in the practice, of course. Barrington Pheloung's theme tune for Inspector Morse effected a musical double entendre on the good detective's name, a furtive audience recruitment initiative that no doubt accounted for the show's intergalactic dominance. Now Dangerfield is at it. If we fail to exercise proper vigilance, everyone will be joining in. A Touch of Frost will be perpetually panning over wintry landscapes at dawn, characters in 99-1 will constantly be betting on unfeasibly long odds down at the dog track, and even Cracker will storyboard an implausible number of paper-crowned Christmas parties.
So it was a clever way for Dangerfield to bow out. The return of the loyal following will have nothing to do with the fact that Paul Dangerfield is plainly nuts about Dr Stevens but doesn't yet know it. He'd better hurry, because if Amanda Redman has to do much more of that sparkling with her eyes she'll be all burned out by Guy Fawkes's Night. Your one worry for their eventual union is that, in Dangerfield's daughter Al, the house already contains one impossibly perfect specimen of womanly understanding: bring in another and the plots will have to inject a double ration of corpses to withstand the deleterious effect of all that goodwill.
At first glance Dangerfield isn't obviously suited to the Friday night schedule, but that's to reckon without the hero's perfect garden and the supporting cast of saloons. Friday being television's pre-emptive equivalent of the Saturday newspapers' sections and supplements and segments, the leisure interests predominate. If Dr Frankenstein wanted to create the perfect Friday-night show, it would be an US sitcom starring Clive Anderson driving a classic car through a magnificent garden. It would be called "Our Man in... American Racing Green Talks Back".
Gardens without Borders (C4) is the latest variation on the horticultural half-hour, The Car's the Star (BBC2) is its vehicular sibling. If you want a job in television, it seems blindingly obvious that you table a proposal to do with either of these two areas and just wait for the green light.
The Photo Show (BBC2) is a snappy magazine focusing on a different leisure interest. Like gardening shows, it assumes a basic level of competence, and can take none of the blame for losing the attention of at least one viewer in the guide to printing your own portraits in the bathroom.
One feature instructed you on the dos and don'ts of getting cute pet shots. The dos appeared to include letting the hound eat off the table, which will doubtless solicit a postbag heavy with tut-tutting missives from Disgusted Dog-owner of Tunbridge Wells. The other do is to borrow the dirty great auto-focussing contraption of the professional photographer who just happens to be showing you the ropes. Next time you take the dog for a walk, remember to get Snowdon to tag along.
But some of the features are genuinely handy. Last week three professionals, including Brian Harris of the Independent, brought back from wet and windy Trafalgar Square the tourist snaps that tourists never get. This week a photographer went behind the glazed, formal portraiture at a wedding and produced a truer, less statuesque portfolio. They'll be requiring her services in the next series of Dangerfield.