"... she... seemed to impersonate Margaret Thatcher...."
Because she's a woman, so, exhibiting political strength, she gets compared to a woman (the only woman who's held her position).
And didn't you — if you watched that and if you're, like me, American — think about Hillary Clinton? Why doesn't Hillary Clinton step up to challenging questioning by opponents? She hasn't even done a press conference — and the press is on her side — since last December!
Well, soon enough, we'll see her in a debate with Donald Trump. She'll have practiced, with somebody who'll be trying to impersonate Donald Trump, and she'll have worked out some steely demeanor to counter his domineering presence. Maybe she'll impersonate Margaret Thatcher.