Brian Johnston has said that his interview was completely unscripted apart from the final question, which was integral to the plot.
The race footage is from the 1949 Derby, won by Nimbus.
During filming Michael Wilding met Elizabeth Taylor who was shooting 'Ivanhoe' at MGM British Studios, Borehamwood. They would marry on February 21 1952, with Anna Neagle and Herbert Wilcox as witnesses.
John McCallum and Googie Withers previously played a similar role of lover and cheating wife respectively in the film "It Always Rains On Sunday" (1947). The couple were married in real life.