Continuity mistake: When the tied up Penelope initially attempts to contact Jeff, you can see two books to the left of the bomb standing up. But when she tries to contact Jeff from the centre of the room, the books have suddenly been knocked over. In the next shot of Penelope the books are standing up again.
Thunderbirds (1964)
1 mistake in The Man from MI.5
Starring: David Graham, Ray Barrett, Peter Dyneley, Shane Rimmer
Trivia: Jeff Tracy's five sons were named after Mercury astronauts - Scott Carpenter, Virgil Grissom, Alan Shephard, Gordon Cooper and John Glenn.