Without You, ITV1

It's your worst nightmare. Two WPCs appear at your door and inform you that your husband has been killed in a road accident. It doesn't help that the one doing the talking looks like the uglier sister of Macbeth's witches. Then they twist the knife by telling you that there was an unknown woman in the passenger seat, now also dead. 

Only moments earlier, Ellie Manning (Anna Friel) seemed to have it all, or about 90 per cent of it. She and husband Greg (Marc Warren) were trying enthusiastically for a baby. She seemed happy in her job as a primary school teacher, and Greg appeared to be getting ahead in the zany world of accountancy with a Manchester firm. But as the coroner at the inquest pointed out, it only takes a moment's inattention to turn order into chaos.

Adapted in three parts from Nicci French's psychological thriller What to Do When Someone Dies, Without You is partly about coping with grief and bereavement, and partly a whodunnit in which Ellie tries to find out what really happened to her husband. None of her friends seem to question the notion that Greg and the dead woman were having an affair, especially since his car was found in a well-known lovers' lane. Even her supposedly closest mate, Gwen (Olivia Poulet), treats her as if she's a nutcase for daring to think anything different. 

It looks as if the story will hinge on our perceptions of Ellie's state of mind. In this opening episode, she was going through a Truly, Madly, Deeply phase of having lengthy conversations with her dead husband, who kept coming back to pay her extremely life-like visits. All part of the grieving process perhaps, like Ellie's tearful visit to the crash site in the middle of the night, or her over-emotional reaction to finding the rocking horse which Greg had secretly bought for her hidden away in the garden shed.

Ellie's gathering obsession with discovering the "truth" might be another manifestation of a disordered mind, especially the way it has driven her to create a map of Greg's movements and activities in the last month of his life by sticking pieces of coloured paper on a large grid. Yet there were a few clues, or wisps of clues, to suggest that her suspicions about Greg's death might not be entirely unjustified. Her husband had no history of infidelity, Ellie couldn't find any trace of the mystery woman (an exotic blonde called Milena Livingstone) when she trawled through his emails, and Milena's husband responded with a bloodless lack of emotion when Ellie tried to quiz him about his wife. He assumed she'd been having an affair with Greg, though without any tangible evidence, and neither this nor her death seemed to bother him much. "I never expected exclusivity," he commented.

Snag was, while the performances - Friel's especially - were strong enough to keep you watching, there isn't enough to go on to make the piece truly gripping. If Greg was merely having an affair, it would be tragic for his wife but not all that fascinating for anybody else. If there is some dark conspiracy lurking beneath the superficial facts, so far we have no idea what it might be. Is Ellie going to go increasingly bonkers over the remaining two episodes? And will we stick around to find out?