The Mousetrap? I hear you ask. That old thing? Why should I want to go and see that creaky old relic? And if you’ve a cynical nature to your character and a sense that theatre should somehow be improving or character-building, then you may have a point. Agatha Christie herself said that its success was largely due to luck, but that it is a play that has something for everyone. In her autobiography, she wrote: “it is well constructed. The thing unfolds so that you want to know what happens next, and you can’t quite see where the next few minutes will lead you.” Christie is being quite modest here!

The play is the result of a distillation of ideas that all started when Christie wrote a radio play entitled Three Blind Mice at the request of Queen Mary in 1947. When Queen Mary requested something, you delivered. This led on to a short story of the same name published in the United States in 1950, which was further adapted and tightened up into The Mousetrap that everyone knows today. The short story, incidentally, has still not officially appeared in the UK because Christie didn’t want it published until after the original run of The Mousetrap had ended; and, of course, that hasn’t happened yet! And this 70^th anniversary tour, currently at the Royal and Derngate all week, is now 72 years from the original production, currently at London’s St Martin’s Theatre, where House Full notices are still regularly posted each night. This play is not going to go away anytime soon.

Obviously, I’m not going to tell you whodunit – we are all sworn to secrecy! However, I can tell you that young Mollie and Giles Ralston have set up a guest house, Monkswell Manor, to make a living for themselves in the harsh austere days after the Second World War. They have four guests booked in for their opening week: grumpy Mrs Boyle, military Major Metcalf, effete Christopher Wren and no-nonsense Miss Casewell; a fifth (Mr Paravicini) turns up unexpectedly, and the house is cut off in a heavy snowstorm. The radio (sorry, wireless) carries the news that a Mrs Lyon has been murdered in Culver Street, London, and that police have a description of a man they want to interview who was seen in the vicinity. Detective Sergeant Trotter arrives at Monkswell Manor seeking information that might connect the Culver Street murder with someone there. But who?

The story was based on the real life case of Dennis O’Neill, a twelve year old foster child who had died in 1945 from violence and neglect at the hands of his foster parents, which led to an overhaul of the fostering legislation in 1947. Dennis’ brother Terence was also malnourished and severely beaten, but fortunately survived. The early drafts of the play included an opening scene, set in London, with extra characters, telling the story of the death of Mrs Lyon. This scene was shortened, and eventually deleted, to be replaced by a simple blackout at the beginning of the play that sets the scene very crisply.

Whilst there have been regular attempts to update the text in the past – increasing money values, changing dates etc – today it is very much performed as a period piece and exactly how Christie originally intended it. Mollie and Giles are still trying to make ends meet with odds and ends of furniture and doing all the work required to run their little guest house in 1952, with post-war austerity and rationing still affecting everyone.  The coke they need to shovel to make the heating work is expensive and poor quality. Trotter says he will check everyone’s ration books to verify their identities. Mrs Boyle sums it up nicely: “this country has gone sadly downhill. Not what it used to be. I sold my house last year. Everything was too difficult.”

Despite its obvious old-fashioned nature, it is a beautifully structured play, designed to establish the greatest possible tension and growing suspicions of everyone – and the solution to the crime holds water too. The characters are a little stereotypical but they’re not at all caricatures, and each one is sufficiently believable to take the audience along for the ride. And there were many moments during Monday evening’s press performance when you could hear a pin drop in the packed auditorium, such was the level of concentration and almost tangible suspense.

However, from a technical point of view, Monday’s performance had a bit of an Act One nightmare: the sound plot simply didn’t work. The opening sound effects of the murder of Mrs Lyon didn’t play. Mollie answered the phone when it wasn’t ringing. Characters turned on the wireless, and no sound came out. Unfortunately, the play relies on the wireless and sound effects a good deal for its opening exposition. Hats off to the excellent cast who carried on regardless, including missing out a brief conversation between Wren and Casewell when they discuss how they used the noise from the wireless deliberately to annoy Mrs Boyle. Luckily, the sound came back shortly before the interval. Additionally, the amplification of the actors’ voices had a bizarre echo/reverb at times which was very disconcerting. Hopefully these issues are now ironed out.

In a show of such reputation as this, the cast are always the custodians of the work, who must look after the production and keep it in good health for future generations. That’s certainly the case here; the cast put in great performances all round. Shaun McCourt is superb in the difficult role of Christopher Wren, trying to make this – on the face of it – rather silly, flippant, overdone character into a credible human being which he does admirably. Todd Carty teeters on the edge of making Metcalf a caricature but reins it in at exactly the right moments. Amy Spinks gives a definitive performance as Miss Casewell, the bullet-proof exterior giving way to genuine emotion when faced with the truth; and Michael Ayiotis is splendid as Trotter, giving a very fluid and confident performance as the police officer with rather alternative methods of detection, building up to a riveting showdown scene. But everyone pulls out all the stops and makes this a thrilling and convincing production.

72 years on, it’s still amazing to hear audience members at the end saying I didn’t see that coming, I thought X had done it, well I thought Y had done it and so on. It may not be the best play in the world. It may, indeed, not even be Agatha Christie’s best play! But as a well-told, finely structured classic whodunit, balanced with a fascinating insight into early 1950s Britain, it just has that certain something that makes it unbeatable. After its week in Northampton, the tour continues throughout England, Scotland and Ireland until August.

Four They’re Jolly Good Fellows!