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"In the portrayal of Jack," Menzies says, "I had to understand the context out of which his behavior comes. It's absolutely having to do with what his men have suffered, what he has suffered and what he's seen. He's seen too much."

And yet, Jack Randall has more in common with Frank Randall than you might think. "I remember the first conversation I had about with [executive producer] Ron [Moore]," Menzies tells us. "He kept saying that he was struck by the fact that these were two men both shaped by war, one by the second World War and one by this insurgency war of the Jacobite rebellion. There are also meeting points. Now, they obviously reacted in very different ways and ended up in different places, but to find some ancestral similarities as well as how they differ was a part of the conversation."

The task of bringing one's mind into such dark places can, of course, take its own toll in real life. "It would be a lie to say that I go home and shake it off," Menzies admits. "But it's what excites me as an actor when I see it and when I manage to do it myself, when there's lots of shades within the colors of the characters. It's true to life, isn't it? Nothing is one thing or the other. Jack is one of life's interesting contradictions. He does have some personal insight, he gets people and how they work but he chooses to abuse those rather than comfort them or reassure them. Diana wrote a lot of strong characters, but Jack is certainly up there."