It was adapted from the short story of the same name by crime writer Agatha Christie which had first appeared in the Daily Mail on 20 November 1928 and first appeared in book form in the US collection Double Sin and Other Stories in 1961.
The play is unique in that it is the only instance of Christie adapting one of her works for television, a medium she later came to dislike.
[1] It was broadcast live from Alexandra Palace as part of the programme Theatre Parade.
Theatre Parade usually showcased successful stage shows of the time but in this instance presented an original work.
The play was only broadcast in the London area as this was the only part of the UK that could receive television transmissions at this time.