The mystery of The Mousetrap is one of theatre’s great secrets – let the cat out of the bag and you get drummed out of whatever the theatrical equivalent of The Magic Circle is. The butler didn’t do it, but that’s all we’re allowed to say.

That the resolution doesn’t come as much of a surprise may be due to the saturation of Christie and the eternal search for clues while watching a murder mystery. Oxford, Midsomer and St Mary’s Mead have inured us to the shock of the unmasking, taught us to distrust our instincts and encouraged us to see through the obvious bluffs.

It’s become such a staple that we’re permanently on the lookout for the tropes we associate with the genre: the starchy old bat, the genial military buffer, enigmatic foreigner and the curiously ubiquitous interwar lesbian. There are red herrings and convoluted back stories aplenty and it’s never really satisfactorily explained just how such an unlikely group of characters ever find themselves in the same place at the same time.

The cast will have you fumbling for the programme in an effort to figure out where you’ve seen most of the actors before. It’s generally strong, though some are clearly better than others, and the direction is happy for the production to wend its own merry way. As a result The Mousetrap sags somewhat in Act Two as most of the characters endure their time under the gaze of twitchy Sergeant Trotter, flesh out their angsty characters and engage in some truly crushing exposition.

Karl Howman may not be recognisable as the apparently-Italian Paravicini but he certainly enjoys the licence that such a rich part allows. Meanwhile Steven France is engaging and lightens the mood whenever he’s on stage as the troubled, flighty (code for homosexual) Christopher Wren and Elisabeth Power is the consummate Mrs Boyle, it’s a shame she’s not in it as much as she might be.

This touring production is the first time The Mousetrap has left the West End in about 400 years; as a result it’s polished enough, but the constant honing and buffing have rather smoothed off some edges. It’s all rather jolly and reassuring, like crumpet at teatime and a mug of cocoa before bed. What dramatic tension or scares there may have been seem a little lost in the mix, though there are some welcome, if gentle, chortles.

As a result it’s not taxing stuff. That’s not to denigrate The Mousetrap in general or this entertaining take, but one hopes that those visiting the Empire this week will broaden their horizons beyond this production. There are far more mysteries to enjoy on the stage beyond this homely whodunit.

The Mousetrap
Liverpool Empre
Until 6 April