The 1972 crime caper was written by John Cleese and Graham Chapman – although they later asked for their names taken off the credits. John Bird and John Fortune provided additional dialogue, and its stars include Spike Milligan, Richard Beckinsale, Donald Sinden.

The plot involves a wealthy scientist who calls in a bungling detective agency to protect both the lab where he has developed a secret nerve gas formula – and his wife. But double-crossing and deception come to the fore when the agency is also employed by the mysterious Madame Greenfly to steal the formula.

The 90-minute film is out on Network, priced £9.99, including the original cinema trailer and promotional material.

To stand a chance of winning a copy, just answer the following question by June 25, when we will choose the winners at random from all correct answers received. Bulk entrants from mailing services will be disqualified. UK and RoI entrants only.