Barely functioning alcoholic Rachel has very few moments in her life which she cares to remember. Instead, she prefers to imagine things vicariously through the lives of others - in small snippets observed from a passing train. One couple in particular catches her eye. Beautiful and successful, from a distance they seem to have everything she doesn't.

In a permanent fugue, and mistrustful of her own mind, one fateful day she witnesses something which sets off a spiralling series of events. Seeing life as she does through the bottom of a bottle, means we can never be sure if what she claims is worth believing.

Adapted from the phenomenally popular hardback which also spawned a hit film, The Girl on the Train fires on all cylinders. In turn vulnerable and belligerent, Samantha Womack delivers a truly harrowing performance as Rachel, a broken woman desperate to make sense of a senseless world.

A full piano score is accompanied by an ingenious scene-change mechanism, whereby the silhouetted outline of a train descends to the internal monologue of Rachel as she pieces her thoughts together, and which stays in the mind long after the curtain falls for the final time.

Faithful to the book and its tight plotting, and accessible to newcomers, this is a thriller which sets an exceptionally high mark for those to follow.

The Girl on The Train is at the Theatre Royal until Saturday. Marion Sauvebois