I had no clue who he was until I saw him in "Braveheart" and my god, he just oozed so much gravitas on screen. He was a pure joy to watch. It wasn't until much later that I found out about "The Prisoner".
We had him as Danger Man, but even before that he was a well known actor in the UK with many films and TV series to his name, he was a regular protagonist in the Columbo and Murder she wrote series.