He rejected attempts to turn his works into movies when he was alive partly because he didn't really care for movies as a form. The board of fellows at King's College who initially inherited the rights to his books after he died in 1970 also did not really go in for having them filmed. But then like a decade after he dies, it passes his other guy who likes movies and at that point it's open season on the M four series novels. So that's where we get the movie we get the view from.