Set in a rolling stretch of English countryside during World War II, a young woman called Alice (Glenda Jackson) takes a young soldier called Barton (Brian Deacon) for her lover while her husband is a prisoner of war In the Far East.
She helps to shield him when he decides to desert and to prevent gossip, she persuades him to dress as a woman and pose as her sister, Jill.
The two of them gradually start to swap sexual roles, so it is the boy-deserter who vivaciously accepts an invitation from a randy roughnecked Military Police sergeant (Oliver Reed) to a dance at the local Army camp. Tragedy inevitably ensues.
The first half of the film is a superbly gentle and loving evocation of a wartime romance, while the second half is a rather kinky melodrama with unfortunate echoes of Some Like It Hot (1959).
The change from pastoral charm to brooding menace is handled very effectively by Michael Apted (in his feature film directorial debut).
The film was shot on location near Salisbury, Wiltshire.
Jenny Lee Wright