Trivia: The "lift voice" heard during the theme song in each episode is that of Stephanie Gathercole, who played Mr. Rumbold's secretary in the earliest episodes.
Trivia: Frank Thornton, Mollie Sugden, John Inman, Wendy Richard and Nicholas Smith are the only actors to appear in all 69 episodes of the show.
Answer: That wasn't possible in 1972. Until recently squatting was a civil offence in the UK, not a criminal one, and removing squatters was a complex and time consuming business.