The Mousetrap is one of those plays that brings with it a sort of legend. The world’s longest-running production has been playing to audiences in the West End since 1952, where it continues to this day, in addition to the national tour that now brings the play to Dartford. Much of its success, I suspect, lies in its air of mystery; as the curtain falls, audiences are kindly requested not to reveal the secret. And while there’s no way to know for sure, it seems most people do keep it to themselves – in a world where social media makes it far too easy to stumble on spoilers (Game of Thrones, anyone?) I’m amazed and impressed that I’ve never caught so much as a hint of the plot, let alone the identity of the murderer.

So in keeping with that, there’s not much I can say by way of summary. A young couple, Molly and Giles, open a guesthouse on a snowy night. As their first guests arrive, news comes over the wireless about a murder committed the day before in London. And that’s about as far as I’m willing to go… but this is Agatha Christie, after all, so suffice to say there are secrets, plot twists and a spooky nursery rhyme, and by the end of Act 1 you can expect to be totally confused about who anyone really is or what’s actually going on.

Now let’s be honest – The Mousetrap isn’t Agatha Christie’s best story. It doesn’t have the creeping tension of And Then There Were None, nor does it feature either of the famous detectives Poirot or Miss Marple, and there are a few slightly frustrating loose ends left dangling at the end of the show. Even the author didn’t expect it to run for more than eight months, so the play’s enduring success is a bit of a mystery in itself. But there’s plenty to enjoy in this traditional whodunnit: an eccentric cast of characters; a set that’s as labyrinthine as the plot; a touch of humour; another touch of danger… and of course, the potential satisfaction to be found in correctly identifying the guilty party. (Not that I’d know – but I assume it’s pretty satisfying.)

Like most Christie plays, the cast in Ian Watt-Smith’s production are very much an ensemble, working together to confuse and misdirect the audience. Oliver Gully is wonderful as the flamboyant architect Christopher Wren – no, not that one – and former Eastender Louise Jameson is thoroughly detestable as the stern and snobbish Mrs Boyle. There’s also an enjoyably bizarre turn from Gregory Cox as Mr Paravicini; both character and actor are clearly having fun in the role of the inevitable unexpected guest.

The Mousetrap is a clever and finely crafted story – but then we’d expect no less from the Queen of Crime. More than that, though, it’s an undisputed phenomenon, and for that reason alone this record-breaking play is a must-see.

The Mousetrap is at the Orchard Theatre until Saturday 21st May.