Harriet Walter doesn't try to mimic Thatcher's accent very closely, which leads to a more natural, less strangulated performance than those of Meryl Streep and Gillian Anderson. She looks too old, but is otherwise fairly convincing. As for Steve Coogan, I agree with another reviewer who says he often just seems to be playing himself. This is sadly true. Despite slight touches of the voice and diction, he doesn't capture Walden's manner as I remember it (and as we see it in those few seconds at the end.) Also I'd have liked more about the 1989 situation and less of the back story that took up episode 1.