According to the commentary by John Hurt on the DVD, real-life retired executioner Albert Pierrepoint was a technical advisor for the execution scene. This scene was the first British people had seen in a cinema of a British hanging, and as it was still covered under the government's Official Secrets Act, no details regarding the scene were available. This is where Pierrepoint came in, under an assumed name, and was able to re-create the harrowing scene to maximize the true terror of what it must have been like.
Richard Attenborough once said of playing John Christie in this film in an interview with "The Times" of London on 18th May 1970: "I do not like playing the part, but I accepted it at once without seeing the script. I have never felt so totally involved in any part as this. It is a most devastating statement on capital punishment".
The film was nominated for a BAFTA Award for Best Supporting Actor for English actor John Hurt. The nomination was Hurt's first ever BAFTA nomination (he did not win) with several others following in his career with Hurt winning a BAFTA next time for Best Actor in a TV role for his part in The Naked Civil Servant (1975).
One of the dust-jackets from Ludovic Kennedy's source "Ten Rillington Place" (1961) book described the story of the Rillington Strangler as follows: "The horrifying and incredible true story of John Reginald Halliday Christie, the necrophile who strangled and then made love to seven women. This is the case that rocked England and the entire civilized world".
The movie's closing epilogue states: "Christie confessed his crimes and was hanged at Pentonville Prison. Twelve years later Timothy John Evans was pardoned, his body exhumed and reburied in consecrated ground".
The actual full real-life name of Richard Attenborough's character was John Reginald Halliday Christie (8th April 1899 - 15th July 1953) and his nick-name was "Reg". The movie was made and released about eighteen years after his execution.
The film was made and released about nine years after its source non-fiction book of the same title by Ludovic Kennedy had been first published in 1961 though the name of the book used a different spelling it being "Ten Rillington Place".
The trivia item below may give away important plot points.
Richard Attenborough portrayed the central character of real-life serial strangler John Christie in this film. Attenborough had previously also played Detective Sergeant Trotter on London's West End stage production of Agatha Christie's "The Mousetrap" who it is revealed to be the killer. Both the real life strangler and the writer of the latter both shared the last name of "Christie".