The Devil at Midnight (Tour – Chelmsford)

Brian Clemens is a master of the psychological thriller, whether on screen or on stage. Devil at Midnight sits us in front of a well-appointed living-room. It's the home of Liz Burns (Corinne Wicks), a psychologist, and her businessman husband, Jack.

Jack has political ambitions, Liz is more concerned with her daughter and new-born grandchild. Enter a patient. Nicki White (Charlotte Chinn) maintains that she has an appointment, though Liz has no record of it being made.

As Nicki is obviously very distressed, Liz agrees to start the session. What comes out – and Chinn plays this scene so sotto voce that you have to strain to hear the words – is a tangle of nightmares, remembered and distressful occurrences, and being taking from her father to live in an institution.

When Jack arrives home, Nicki's reaction is extreme. Eventually, Jack and Liz go out to a function at which he intends to further his possible parliamentary career. When they return, so does Nicki. But this time, it transpires, she has brought an ally, her brother Billy (Chris Sheridan).

If you don't know the story, then I won't spoil its outcome – or the plot twists and turns which lead to the dénouement. Chinn has a very long speech towards the end which does come over clearly and is vital to our appreciation of the issues raised and our instinctive reactions to each one.

Director Patrick Kearns keeps the momentum going, though I would have dispensed with the use of incidental music – but that's purely a personal opinion; it annoys me equally in television dramas. Set designer Geoff Gilder combines the naturalistic with a fractured skyline and door-frame which suggests that an Englishman's home may be a castle. It can also resemble a prison.

The Devil at Midnight tours nationally until 19 July.