Miranda Richardson knew there’d be some pressure in taking on the role of Barbara Castle, Britain’s first (and so far only) female secretary of state, for the new Brit flick “Made in Dagenham” — but she wasn’t about to let it get to her. “I was aware that she meant so much to many people, but you just have to get on with it, you know?” Richardson says, shrugging.

In researching Castle’s life, though, Richardson found inspiration. “I read a biography, looked at photographs, newsreel footage,” she says. “And in the silence of reading about her and looking at photographs, staring at them and trying to make them sink in, I just thought she was the most wonderful woman and would’ve loved to have met her and gone out on the town with her. I think she would’ve just been enormous fun.”

Aside from taking on the historic role, the subject matter of the movie was something close to Richardson’s heart: “Made in Dagenham” chronicles the struggle of the female factory workers at Ford’s largest British plant as they pushed for equal pay and respect. “I think it’s quite interesting, the self-esteem aspect of it,” Richardson says. “It’s even something that I used to grumble about when I was working with a predominantly [Oxford and Cambridge] team on ‘Black Adder.’ There’s the famous thing where guys don’t feel that women can be as funny, certainly in the stand-up routines, but there’s also a really stupid thing about, ‘Oh, they’re marvelous, the girls are absolutely marvelous. They’re just not always as good as the boys.’ I think it’s always there, it’s always working. And if somebody thinks it’s the way things are and is not told differently, then things go on the way they are for a long, long time.”