Although the Ambassadors opened in 1913, construction of the St Martin's was delayed by the outbreak of the First World War.

The theatre is still owned by the present Lord Willoughby de Broke and his family.

The first production at the St Martin's was the spectacular Edwardian musical comedy Houp La!, starring Gertie Millar, which opened on 23 November 1916.

Successes at the theatre included Hugh Williams's play (later a film) The Grass is Greener, John Mortimer's The Wrong Side of the Park, and in 1970 the thriller Sleuth which starred Marius Goring for a long run as Andrew Wyke.

[4] In March 1974 Agatha Christie's The Mousetrap transferred from the Ambassadors to the St Martin's, where it continued its run until 16 March 2020 when the show had to be suspended due to the COVID-19 pandemic in the United Kingdom, holding the record for the longest continuously running show in the world.