The survivors of the initial storm surge battle to stay alive as the water thunders up along the Thames and out across the city. Leonard Morrison ends up in the Cobra control room trying to anticipate the devastation and come up with a plan to mitigate it. That plan requires the opening of sluices higher up the Thames to create an opposing surge of water that will wash the tide back out to sea, but first the inoperative Thames Barrier will have to be restored.

The soap opera storylines are put into abeyance in the second part of this thriller, allowing the characters to get on with the job of nearly dying a lot in the water and running around the control room demanding information and giving orders. The dialogue is less awful than much of what was in the first episode, but the plot does require the characters to do a lot of silly things. What nobody does, however, is ask how high the water is going to be and send people up the nearest tall building. And nobody explains how Jessalyn Gilsig can spend hours in freezing water with nothing more than a silk blouse and not catch as much as a chill.

The traditional disaster movie roots come out all the more in this second episode as characters escape by the skin of their teeth, or through the sacrifice of others, jumping from one dire disaster (watch out for that falling car, crawl quickly up the flooding pipe, escape from the dead end room, pass Go and collect £200. Events in the control room are more believable and provide the stronger drama as those who are safe are forced to make decisions about people's lives. Joanne Whalley dominates this section, with able support from David Suchet.

The plot isn't afraid of killing people off either, sometimes unexpectedly. There are some surprisingly suspenseful moments and also some surprisingly powerful scenes of loss, usually the ones where the actors are allowed to get on with it without being hamstrung by the poor dialogue.

Scenes of the drowned London are impressive, but the disaster seems to be dragged out a bit as the surge continues up the Thames even after the storm has turned away. The pace drops off alarmingly and the threat no longer seems to register.

And just how stupid are engineers anyway? Who designs a backup system that lies beneath the waterline and only works when the room is sealed? And why didn't anyone think to bring a few more aqualungs along? They might have come in handy.

FLOOD won't be going down in the disaster hall of fame, nor probably feature highly on any of the actors' CVs in future, but it does enough to be a successful time passer.