Three criminals plan to break out of prison the day before their release in order to carry out a daring jewel robbery, intending to establish the perfect alibi by returning to jail afterwards. First however they must get out, a task made more difficult by a new, stricter prison officer.

• Vale Film Productions
• Shepperton Productions
• Peter Sellers
• Maurice Denham
• Lionel Jeffries
• David Lodge
• Bernard Cribbins
• Wilfrid Hyde-White
• Irene Handl
• George Woodbridge