Entering the Watermill's auditorium often provides a frisson of excitement, for designers seem to be inspired by the challenge of fitting extraordinary sets into this small intimate space. Thanks to Simon Kenny's wonderfully detailed set, the audience for Anthony Shaffer's brilliant deconstruction of - and hommage to - the quintessentially English murder mystery finds itself apparently actually inside one of those country houses so beloved of writers of the genre.

In this case it's the home of fiendishly clever murder mystery writer Andrew Wyke. Director Jessica Swale says that part of the fun was to take advantage of the Watermill's country house setting; Kenny serves her and the play to perfection. Shaffer wrote Sleuth in 1970 and Kenny's design also sets the play firmly in that decade, right down to the executive ball clicker toy on Wyke's desk.

Richard Attlee's flamboyant, unpredictable Wyke is very much at home in these tailor-made surroundings and (unsurprisingly) Matthew Spencer's seemingly callow youth Milo Tindle appears equally uncomfortable and out of place. Tindle has accepted an invitation from the man whose estranged wife he's stealing away only to find himself discussing not just "wife theft" but also an intricate plan to steal her jewellery too as part of an insurance scam, so his discomfiture is not surprising.

Wyke wants to play with Tindle - but does he see him as a playmate or a plaything? Actually it's both, for Wyke is an inveterate game player (and we're not talking computer games!). He could be rehearsing ideas for his next book – or he could be in deadly earnest. So in the first half of the play, Wyke runs rings around Milo. Neither is especially likeable, for Wyke is a snob and a racist, disparaging about Tindle's Italian-Jewish parentage, at ease with terms like "wop" and "yid" and Tindle is a cocky, unprincipled young man, quick to fall in with Wyke's scam.

The plot soon thickens and events seem to spiral out of control, so that at the end of the first half the country house is a shambles and things look bad for Tindle. Does he live to turn the tables? Does Wyke get his come-uppance? And who is the authoritative Inspector Doppler (a convincing Stewart Cheem) who takes over after the interval?

It would be a crime to give a spoiler for those who've never seen Sleuth. Suffice to say Attlee and Spencer ignite the stage, sparking off each other as the advantage see-saws between them, and the menace and tension are unsettlingly real, enhanced by Isobel Waller-Bridge's suspenseful music and sound design and Nick Ritchings' mood-changing lighting. It's an evening of killer lines and Swale's imaginative, inventive direction complete with all sorts of delicious monkey business ensures the audience laughs a lot - although I'll not reveal who gets the last laugh.