The show is a fairly faithful adaptation of the original story where Edward Robinson, a city clerk much under the thumb of his fiancée, Maud, decides on a whim to spend some competition prize money to buy a sports car. He takes it to the country for a drive and then when coming back, he finds. to his surprise, a diamond necklace in the pocket.
(may contain spoilers - click on expand to read)
The show is a fairly faithful adaptation of the original story with many additional characters to flesh out the story but which don't alter the main plot.
- The car which Edward buys is not scarlet but a white Riley. The price is, however the same.
- After Edward buys the car, it is his friend Herbert Maynard who teaches him to drive. He also persuades him to go for a tour of Surrey.
- Edward tells Maud he is skipping Christmas with Maud and her mother because he has to help look after Herbert Maynard's ailing parents who live in the country. However, Edward's cover story is busted when Herbert comes to Maud's house to take a Christmas collection. Maud's mother asks about his parents and Herbert says his parents are not ailing and don't live in Surrey. In the original, Edward's cover story is never busted.
- Edward doesn't go for a walk at the Devil's Punch Bowl. Here he stops at the Tantalus Hotel in Surrey. He goes to the bar for a drink. Agnes Larella actually has a room in the hotel and the theft takes place here.
- After the theft, Lady Noreen and Edward don't go to Ritson's but to Cafe Paris. There is an added plot embellishment here where some of Noreen's friends try to get the necklace away from her so that she does not win the wager.
- Lady Noreen and Edward part in the same way. Here she actually goes further and wants Edward to take her away with him for what she thinks would be an exciting life of crime. However Edward dissuades her. They part on the best of terms but here she does not actually give him a passionate kiss.
- Besides Maud, Edward also has to deal with her fairly intrusive mother in this adaptation. And here also, Maud actually likes the idea of a car and suggests that they go out for a drive together.
- Nicholas Farrell as Edward Robinson
- Cherie Lunghi as Lady Noreen Elliot
- Margery Mason as Mrs Lithinglow
- Ann Thornton as Maud
- Tom Mannion as Herbert Maynard
- Sallyanne Law (credited as Sally Anne Law) as Millie
- Patrick Newell as The Major
- Bryan Coleman as Lord Melbury
- Nicholas Bell as Jeremy
- Rupert Everett as Guy
- Fiona Hendley as Poppy
- Simon Green as Sebastian
- Georgina Coombs as Diana
- Rio Fanning as Barman
- Frank Duncan as Grosvenor
- Julian Wadham as Gerald Champneys