The Mousetrap
Quite rightly, St Martin’s Theatre, home of the long-running play, The Mousetrap,

Another of London’s theatres designed by W.G.R Sprague is the St Martin’s Theatre in West Street. It first opened on 23rd November 1916 with a comedy called “Houp La” At this moment, and for the last forty three years, it is home to the world’s longest running play, Agatha Christie’s “The Mousetrap” which transfered to the theatre on 25th March 1974. More information
St Martin’s Theatre, West Street, London, WC2H 9NZ