"If you want to grow, stand in manure," Spider, a Swampy lookalike, said to his prim and proper aunt, peering from behind her front door into the darkness. "I've been putting my foot in it all my life," he joked as Emily Bishop glanced anxiously at her well-polished step. Poor Emily. Having finally evicted crusty old Percy Sugden, the desperate scriptwriters on Coronation Street (ITV) last night camped this younger Crustie in her back garden.

It's all part of the relentless modernisation of British television's oldest soap. So the hour-long special closed with the bleak shot of an infant left alone in a freezing squat, a scene recalling the sordid death of a baby in Trainspotting.

Last night's episode was scheduled to wrap around EastEnders and so dissuade soap addicts from switching to BBC1 at 8pm. But clever programming cannot disguise continuing dramatic deficiencies in Weatherfield. This double-length edition featured major plot developments. Teenage mum Zoe stole her baby back from its surrogate parents, the Malletts; while spineless dad, Kevin Webster, deserted his lover Natalie as a first step towards returning to his wife Sally. All gripping stuff - except that EastEnders does it so much better.

The surrogacy line has always seemed improbable even by Coronation Street's tall story standards. And pain of childlessness was more profoundly explored recently in EastEnders, when Bianca had an abortion after her baby was diagnosed with cystic fibrosis and encephalitis. Scenes of the induced- labour abortion, which Bianca at first fled when she felt the baby move, marked some of the most moving soap moments of 1997. When it comes to marital infidelity and child abduction, the web of Cindy Beale's deceit in EastEnders and her fight for the children have been compelling viewing. And even this serious subject has retained a comic undercurrent. Phil and Grant may have been busy stealing children in Italy but that didn't stop a few hilarious scenes as they bumbled around the countryside getting into Carry On-style tangles with alcohol and the carabinieri.

In contrast, Kevin Webster's adultery, though initially believable, was accompanied by a sudden disdain for his wife that required a character flip matched only by its equally sudden reversal last night. And the saga lacks the comic relief that once so distinguished this soap from its too earnest BBC rival.

Those who say Coronation Street has been resuscitated after the near- fatal departures of the beehived Bet Lynch, the innocent Raquel and the naughty Reg Holdsworth can point to the introduction of younger characters - Spider's arrival looks promising - and a long-overdue clear-out of dead wood. But the northern soap has yet to regain the strength its southern rival can now claim from well-drawn, established characters. Worse, the failure to turn Vera Duckworth into a serious matriarch at the heart of the Rover's Return deprives the Street's disparate plots of the links they had when anchored there by Bet Lynch. It's time to give Vera a character makeover.

Equinox (C4) revealed how industrial espionage has replaced Cold War spying as a preoccupation both of some governments and American counter- intelligence agencies. Conspiracy of Science featured FBI stings targeted at disloyal insiders within biotechnology firms. Those who try to sell the secrets of genetically engineered drugs to exotic-sounding individuals find, in the tradition of Candid Camera, that they have, in fact, been dealing with the local Plod. In the land of freedom of speech and information, the police now reckon that protecting the huge potential profits of new drugs is a higher priority.

Tim Shawcross's film inevitably made the viewer wonder what else - nuclear material, for example - is being lugged around in suitcases for cash. And I couldn't help thinking that revealing these pharmaceutical secrets, so making vital drugs cheap to the poor, had an arguable moral defence which this documentary avoided. The film did, however, detail the heavy- handed censoring of scientific information about the side effects of drugs, which sound very like the efforts made by tobacco companies to control damaging publicity. By the end, any redundant, left-leaning spy would surely have spotted a fresh challenge at least as honourable as his old job.