Incest. One might even now be startled to find this the underlying theme of Banana Ridge (1941) which had appeared in the West End three years earlier. All the more so as it is a farce with the requisite number of doors - and even a wardrobe.
Ben Travers had a long series of these produced at the Aldwych Theatre in the Twenties and Thirties. Most were filmed, and are often dismissed as stagey when in fact they are more than a record of the era's acting styles. Robertson Hare and Alfred Drayton are part of a company which deals in rubber (with the former on leave from a Malayan plantation). Along comes a charmingly insinuous Isabel Jeans, who reminds them of their lodging at her mother's house as officers during the Great War. It appears that either of them could have sired a son upon her (Jeans) – the very fellow (Patrick Kinsella) who is waiting outside, and even then beginning to romance Drayton's daughter (the great Nova Pilbeam) – and he simultaneously would Drayton's wife, Pilbeam's mother.
Small wonder that Drayton is aghast at his possible son marrying his certain daughter. Hence his being bundled off to the eponymous plantation (by dint of a money and some rain showers, this was filmed in Hertfordshire). All concerned give dashing performances (literally and metaphorically), not playing it for laughs but taking it seriously, which is the necessary requirement of effective comedy.
And it is a repository of vanished phrases. When one wife tells another that she does exercises every morning, she is asked, “don't you find that terribly heating?” And one husband, when told to do something, expostulates, “I'm sugared if I'll do so!”
Travers was to have a revival in the Seventies – and, at the age of ninety, a new play, directed in the West End by Lindsay Anderson. If at the moment, sightings of them are rarer, these film versions are a chance to discover a master of mayhem.