I saw this movie back in the late 1970's at around 3 in the morning! It caught my attention right away the haunting whistling tune the flashbacks! Dirk Bogarde was just fabulous! Convincing as both characters!!! If you haven't seen this movie please make a point of watching it!!!! I'm watching it again now on TCM! And I still find it haunting 40 years after the first time I saw it!!! A must!!!