Flood, Sun, ITV1Peep Show, Fri, Channel 4

Oh, the humanity! It's never the desk jockeys and back-room administrators who suffer when a disaster strikes. It's the poor sods on the front line, who have to put into action what may well have seemed like a good idea on paper but turns out to be lethal in reality. Take Flood, for example, ITV1's compellingly awful mini-series about the inundation of London. The writers, Justin Bodle and Matthew Cope, remain relatively sheltered from public opprobrium, their names featuring only in a brief on-screen credit, along with the director and producers. And the ITV executive who actually green-lit the project enjoys total anonymity as far as the viewers are concerned. But the poor actors find themselves with nowhere to hide, exposed to the full ferocity of the storm for hours, tumbled along in a maelstrom of implausible plotting and breath-stopping dialogue. They're the ones that are going to need the trauma counselling when the water finally recedes.

Flood began with a tsunami in Wick, West Sussex, brushing aside a tidal-measurement facility before rampaging inland to drown someone's granny and force her daughter up into the attic, the first of the glut of estranged and imperilled relatives that the drama had lined up for us. In this, it was only obedient to the usual disaster-movie rules, which insist that while the heroes battle against fire, flood and volcanic eruption, they must also hump around with them large amounts of emotional baggage. Robert Carlyle, unlucky enough to have landed the central part of a hydraulics engineer, had actually been equipped with two simmering family feuds: one with his former wife (who appears to run the Thames Barrier) and one with his father (a tidal expert who told everyone that the barrier was being built in the wrong place, but they wouldn't listen, damn them, the fools, the fools). And, naturally, they all ended up in the same place when apocalypse finally reached London.

David Suchet, meanwhile, was stomping around the Cobra operations room playing the Deputy Prime Minister, a man whose sole duty appeared to be to ask simple-minded questions so underlings could feed statistics and information into the drama. "Sorry... storm surge?!" he barked irascibly, and a shamefaced woman from the Met Office powered up a laptop conveniently loaded with a CGI graphic of several billion tons of water barrelling towards Southend. The DPM was understandably cross that he hadn't had more warning that the capital might be wiped off the map, being informed of the city's imminent destruction with only three hours' grace. Then again, physics does seem to be flexible affair in these things. "We need to relocate now!" snapped Joanne Whalley, as a tidal wave travelling at 50 miles per hour sailed past Tower Bridge towards her Whitehall ops room. Six minutes later, they appeared to have a fully functioning crisis-control centre up and running somewhere else, the tsunami having graciously pulled up in the Pool of London for a while to allow everyone to make the move. And though the storm surge was powerful enough to flick juggernauts aside like bits of popcorn, it was also sufficiently placid to allow Robert Carlyle to go duck-diving in the Thames to look for a lifeboat. Absolutely nothing made sense: in one shot, the city streets were gripped by mass panic and gridlock, in the next, Joanne Whalley's daughters appeared to have been able to hail themselves a taxi, something that can be tricky even in light drizzle. Curiously, one man escaped entirely unscathed, the beneficiary of one of those arbitrary miracles that sometimes occur in natural disasters. For some reason, Tom Hardy, playing a hapless Tube worker, was given lines that actually sounded like something a human being might utter, and as a consequence was able to deliver a performance that he'll be able to look back on without wanting to pluck out his eyes. The rest of them went under, and the only blame that attached to them is that they didn't run like hell for high ground when they saw the damn thing coming.

Peep Show returned on Friday evening to further explore the almost limitless sleaziness – moral, physical and intellectual – of Jeremy and Mark. This week, they found themselves locked into a double date at the theatre, a prospect that appalled Mark. "Relax," Jeremy reassured him. "It's all different now... they've moved on. They use proper actors, you know, Americans, and people off the telly, and they're all based on films, so its fine." In fact, the play turned out to be Othello, which prompted Jeremy to walk out in disgust and then express a rapture that I don't think I've ever seen acknowledged in print or on air before, that of the theatrical escapee. "I wasn't even meant to be out till 11 and it's not even nine! I've time- travelled! I've made time!" Scabrous slapstick and base motives are the core of the comedy, but that kind of leftfield detail is what gilds it.