What makes The Mousetrap the longest running play in history?

I am amongst the throng of theatregoers curious enough to want to see The Mousetrap because it’s billed as the ‘world’s longest running play’. It has also been on my ‘must see’ list partly because it’s a whodunnit Agatha Christie play but mostly due to intrigue. Will The Mousetrap justifiably run until Domesday because, like the Crown Jewels or the Mona Lisa, you feel the need to see it because it’s the done thing? Like taking a selfie while hanging off The Eiffel Tower (kids don’t do this) or leaning at a ridiculous angle in front of the Leaning Tower of Pisa just so you can post, share and let’s face it, show off.

So what is there to brag about The Mousetrap and why is it so-named?

In my early teenage years I avidly read Agatha Christie novels. I loved the classic twist in her thrillers from And Then There Were None to Witness for the Prosecution, Death on the Nile and Murder on the Orient Express but I never knew the storyline to The Mousetrap.

The play breathed life after Dame Christie was asked to write a 30-minute radio drama initially entitled Three Blind Mice for Queen Mary’s 80th birthday in 1947. Five years later it ran as a play and 67 years later it’s still wowing theatregoers.

The opening scene is set around the 1950s and introduces the audience to Giles and Molly Ralston, who are somewhat on tenterhooks because today is the grand opening of their guest house, Monkswell Manor. The guests arrive one by one during a snow storm and as the weather condition worsens the inhabitants find themselves cut off from the outside world. On the wireless (old-style radio) we are informed a woman has been murdered. Another murder of an annoying, over-critical woman takes place in the Manor (truly we’re all glad to see her bumped off if only to rid us of her constant whining) and we soon discover that the murderer and next victim may be under the same roof. With a third and final murder anticipated there is a race against time to discover the identity of the murderer.

As can be expected of all murder mysteries, the closer we get to learning the identity of the murderer the more layers are peeled of each of the characters and the more we suspect that not only could they be potential victims but also potentially the murderer. Oooohhh.

Television (Emmerdale, Bouquet of Barbed Wire) and established stage (Cabaret, Dangerous Obsessions) actress Susan Penhaligon plays whiny Mrs Boyle to perfection. There’s foreign-accented Mr Paravicini who turns up after his car becomes stuck in a snowdrift. “I am the man of mystery, the unexpected guest”. Detective Sergeant Trotter turns up in skis, desperate to catch the criminal before another murder takes place. Retired soldier Major Metcalf who’s yet another mystery and Mollie Ralston, played by Harriett Hare (known for gaming and animation voiceovers such as Game of Sultans and Warhammer’s voice of Morathi), also star. Mollie’s voice and manner is in perfect keeping with the time and a rather polished performance, dare I say. Saskia Vaigncourt-Strallen, (Susan in Harry Potter and the Order of the Phoenix) plays Miss Casewell, a sexually ambiguous woman who is clearly facing some distress but showing a steely, brave front.

Drama graduate Lewis Chandler, making his UK tour debut with the show, plays a camp guest claiming to be the namesake of St Paul’s Cathedral architect Christopher Wren. He turns up wearing bright yellow trousers and a woollen tank top occasionally throwing a hysterical laugh while tossing his head which is somewhat reminiscent of a homicidal maniac. Lewis should be congratulated for being so convincingly crazy.

As the play chugs along there are more questions and less answers until it all becomes clear at the very end. Incidentally, the cast asked the audience at the end of the play, as a tradition, to kindly refrain from revealing or even hinting at the identity of the killer. That’s when it dawns on me. This tradition of the cast speaking to the audience at the end is what makes the play so alluring. They engage with the audience and in turn the audience now have a duty to (not) pass on.

So the best-kept secret in theatreland is the secret of its success me thinks. You be the judge.

On at Glasgow’s Theatre Royal from now until Saturday 2 November