Jimmy Carrol (George Cole) paraphrased lines three and four of Lord Alfred Tennyson's "Sir Galahad" (1842): "Our strength is as the strength of ten, because our hearts are pure."
In pre-production, this movie was called "The Cautious Amorist" after the novel on which it was based.
George Cole was originally cast in Kenneth More's role and vice versa. But the actors liked it better the other way round and changed their respective parts for the final version of the film. They had originally been typecast, but they changed it so they were cast against type.
Hattie Jacques, who played Dame Joan Collins' mother, was only eleven years older.