Yes, I too saw it in 1987, aged 22 and certainly it had a tremendously powerful effect on me. As you say, seems impossible that it would be made today, but those were the days of true investigative journalism ('World in Action', Paul Foot, Pilger in his prime etc.), and before Trevor McDonald and Stacey Dooley were considered grand inquisitors. I did know about the warden's crisis of conscience and conversion, but had forgotten, so thanks for the reminder.