If you are going to conduct an illicit affair there are probably better places to do it than the grounds of a high-security psychiatric hospital. With one of the patients.

Still, it doesn't seem to bother Stella (Richardson), the skittish wife of Max (Bonneville), an ambitious psychiatrist whose just landed the post of deputy at a northern asylum.

Trapped in both a coldy formal marriage and the walls of the Victorian institution, she strikes up a rapport - and a hint of something more - with inmate and gardener Edgar Stark (Csokas).

If you are going to have a fling it's probably best not to have one - no matter how good the sex - with a wife-killer suffering severe personality disorder featuring morbid jealousy.

However, after one hurried coupling on the floor of the asylum greenhouse their attraction grows into a passion so all-consuming it destroys anyone who gets in its way.

The only cautionary voice of reason comes from Max's rival shrink Dr Peter Cleave (McKellen)... but he harbours feelings for Stella himself.

Soon Stella's blind love is threatening her arid marriage and even her relationship with her adored 10-year-old son Charlie. But there is no way back.

Scottish director David Mackenzie dealt with the subjects of obsession and lust in the impressive Young Adam but here he struggles to find the right note despite Patrick Marber performing screenplay duties.

One of the main problems is Stella's relentless downward spiral, a trajectory that loses the viewers' interest as she plummets without respite from ill-advised, to bad to tragic.

It's also difficult to empathise with a woman who would value a doomed relationship with a vicious psychopath over her responsiblities to a young son - even if her husband is a boorish prat.

Even so, there's no denying the emotional power of the climax - Stella's helpless desperation and Edgar's terrifying reversion to type.

Who was it that said love is madness?

Tim Evans