Emma Thompson is, essentially, a British institution. Hopefully that doesn't sound derogatory because it's certainly not meant to. Actually, even if it did, you get the impression that Emma would take it in typically self-deprecatory fashion because, in an industry that produces so many deadly serious types, Emma still comes across as a breath of fresh air.
So while some actresses would be daunted at stepping into Claire Bloom's acclaimed shoes as Brideshead Revisited's domineering matriarch Lady Marchmain, Emma laughs off such concerns. Yes the TV series is iconic but "I didn’t even see it!" admits Emma. "I was 20, I was a punk rocker. I was trailing around London in a lot of zips..."
It's not difficult to see why Emma was so keen to play Lady Marchmain. It's a great, meaty role, that's equal parts religious zealot and matriarch. In Emma's hands though, she becomes a far more human creature than you might expect.
"I worked out – this morning actually, which was a bit late – that the thing about Marchers (as I like to call her) is that she really does believe if she doesn't do right by her children, they will go to hell. In the same way that I believe if I do not prevent my child from running out in the road she will get run over. So I pursue her with the same vehemence in relation to cars as Lady Marchmain pursues her children in relation to anything, from food to sex, to marriage to whatever.
"She believes she's doing the right thing, that she's giving them the tools with which they can save themselves. While her emotional methods are cruel to the point of psychosis, she does believe she's doing the right thing for all the right reasons." Emma grins. "It's the religious version of the Green Cross Code."
The film version has some similarities to the series, most obviously in the locations used. Once again Brideshead itself is 'played' by Castle Howard and Emma clearly enjoyed her time at the house.
"Castle Howard is so interesting because it's run as a business now," she explains, "and the difference between swanning around it now and when Lady Marchmain was in charge was that Lady Marchmain lived in it. As in IN it. I mean, in a way the Queen doesn’t live in Buckingham Palace.
"They'd have to have the Gilt Room opened (for the Queen) whereas missus would have been wandering around wherever she wanted with vast quantities of servants, like Lady Astor."
These days though, Castle Howard is very much split into two: the façade the public see and the behind-the-scenes areas.
"It’s like a theatre," adds Emma. "We were living, as it were, partly in the bit which is run like a theatre, and partly in the bit where they keep the J-cloths. And the linoleum."
She smiles. "I've been 'backstage' at Windsor Castle and there's a LOT of linoleum. A surprising amount, considering…"
* Brideshead Revisited is open now in cinemas nationwide.