John and his class visit the Tower of London, where he loses his pet mouse. He falls asleep during a lesson on electricity, but with some help, he learns about it, invades the Tower, and saves his pet.
Mark Dightam
John
Robert Eddison
Nick
Helen Weir
Mrs Saunders
Brian Worth
Mr Saunders
Esmond Knight
Doctor
Laurence Carter
Schoolteacher
Patrick McAlinney
Supreme Beefeater
Lem Dobbs
Munro
