Bet it was controversial when it came out

Found this gem on youtube. It's quite obvious where the twist is heading from about 5 mins in to our 2019 eyes, but I imagine at the time it came as a great surprise.

Referring to my title, it seems the subject of the flashbacks would have been a shock to see as such things were rarely portrayed on tv so vividly.

If you've 90 mins to spare and like a good old thriller you should find this out 👍