"I had very bad luck with this film of my first book because Alfred Hitchcock, a very old friend of mine, when I had sent him a copy of the book immediately decided he wanted to make the film. But unfortunately he was about to change companies, so asked me to hold it for some months, which I did. He then asked me to lunch at the Carlton with Richard Wainwright and his father, who had been the head of UFA films ... ... ... Wainwright agreed to buy the film rights and then went straight down to my agent and signed the contract, but ... ... ... one thing was left out, that Hitchcock should make the film. Later, when Wainwright had engaged floor space and stars, the company to which Hitchcock had gone would not release him to direct the film."
Letter to Lars Nylander 9th February 1973