In a small west country town, Lester Small is a driving instructor with quite a reputation - for taking clients that cause havoc and mayhem whenever they are on the road!

His most consistent client is Mrs Davies, a one woman disaster zone who does nothing to help ingratiate Small with the Chief Inspector of the local police - with whom he has a long standing feud.

Unfortunately, Mr Davies is Lester's bank manager, and rather has him over a barrel to keep on teaching her until she passes her test: a circumstance, by his own admission, significantly less likely than the Thames beginning to flow backwards...