One of the delights of The Mousetrap is that while it might be the world’s longest-running play, it also contains one of the planet’s best-kept secrets. Because if you’ve never seen Agatha Christie’s classic murder mystery – and I hadn’t until tonight – then chances are you don’t know whodunnit.

Theatre-goers have kept tight-lipped on that particular matter for 70 years in a pact of secrecy that only adds to the enigmatic charm of a show that remains exclusive to those same audiences. The cinema crowd have never got to see it because even though the movie rights were sold in 1959, they contained a proviso that a film couldn’t be made until the London stage production had been closed for at least six months. And that’s never happened (recent Covid interruptions notwithstanding).

There’s surely a mystery thriller, or at least money, to be made from forcing its closure so the film version can get the green light, but who would dare do that? And how? Could it be as simple as breaking rank and revealing the identity of the killer?

While you’re pondering those mysteries, how about another conundrum: where were the best-known stars of the show on its opening night at the Belgrade? Both Todd (Tucker Jenkins/Mark Fowler) Carty and Gwyneth (Only Fools and Horses’ Cassandra) were ‘indisposed’ for the performance I saw, which somewhat spoiled my plans to imagine EastEnders’ cliffhanger drumbeats at every dramatic revelation.

And there are plenty of dramatic revelations in this consummately-performed touring production – understudies Nicholas Maude and Judith Rae slipping seamlessly into proceedings alongside excellent performances from the likes of Joelle Dyson (another former EastEnder) and Joseph Reed – which sees seven strangers snowed in at a remote country guesthouse as news of a gruesome murder in London is relayed over the wireless. The arrival of a police sergeant suggests the killer is among them – as well as his potential victim or victims – and we’re soon in the thick of the mystery, trying to solve the crime before he does.

Everyone could’ve done it of course, everyone has a secret, and there are more red herrings than Billingsgate Fish Market, but that’s all part of the fun, and while some of the laughs (a murder scene?) and caricature characters are dated, and the background plot perhaps a little dark for something so light, there’s a feelgood nostalgia to proceedings that means the legendary play – and the secret at its heart – remains something to hold on to.

3 stars

Reviewed by Steve Adams at the Belgrade Theatre on Monday 13 February. The Mousetrap continues to show at the theatre until 18 February.