When Agatha Christie’s murder mystery play The Mousetrap opened in London in 1952, the actor Sheila Sim, who has died aged 93, had doubts about its ability to last for six months. But the fact that she could wait until just before its 50th anniversary before publicly confessing those doubts, at a lunch at the Savoy hotel with 300 other actors who had appeared in the play, showed them to be unfounded. By then it had long passed its 20,000th performance, and it is still going strong, as the world’s longest initial run of a play.
Through starring as Mollie Ralston, owner of the snowed-in Monkswell Manor, Sim set the seal on her growing reputation as an actor. Her husband, Richard Attenborough, co-starred in the play as Detective Sergeant Trotter, who arrives on a pair of skis,