This was the most successful British-made film at British box office in 1974.
When he signed onto this film, Robin Askwith was contracted to Columbia for a six-picture deal, which was unheard of in those days. The only other British actor at the time with a similar deal was Sean Connery. Askwith said in a 2005 interview that he never expected the film, which he called "a load of old twaddle," to be successful. The next two sequels made even more money, but then the box office dipped slightly for the fourth one, so they stopped making them.
Robin Askwith said in an interview that he had to simulate sex 850 times per film because they had to shoot three versions for every sex scene: one completely naked for the UK, one with his pants on for abroad, and one completely clothed for South Africa and Rhodesia.
Among those who turned down the lead role were Dennis Waterman, Richard Beckinsale, Richard O'Sullivan and, according to his own account, Nicky Henson.
Executive producer Norman Cohen was originally going to direct the film, but was persuaded to step aside in favor of the more experienced Val Guest. Cohen would instead direct the film's three sequels.