She notes that in “those more treacherous times” she received no support from older actresses. “There was no sisterhood when I was starting out.” In fact, Walker often encountered rivalry between women of the sort dramatised by Bridgerton’s sparring matriarchs. She was particularly stung by the cruelty of “one huge female star” when she was shooting in LA in her mid 20s. “I’d been dressed in this amazing Azzedine Alaia suit and she took one look at me, shook her head, and said: ‘No. Your character wouldn’t wear that.’ I was sent back into my caravan and put into a much dowdier outfit.”

Walker’s career began to pick up pace again when, aged almost 40, she starred as the devious, seductive Atia (niece of Julius Caesar and lover of Mark Antony) in HBO’s swords-and-sandals soap opera Rome. Hailed by one entertainment website as “the biggest bitch a TV series has ever produced”, Atia wielded her sexuality as a weapon, used her own children as pawns and, memorably, whispered an earnest wish for her enemy, Cleopatra, to “die screaming, you pig-spawned trollop”.

Today Walker says she often hears that “people see Atia as a forerunner of the strong, strategically minded female characters in Game of Thrones. Complicated, wicked, vulnerable.” But the actress says she hasn’t needed to use any Atia-esque cunning to remain in the game. She attributes her longevity as a screen siren to “high standards when it comes to scripts, refusal to be involved in misogynistic projects and not paying too much attention to celebrity.”

Walker describes herself as a “survivor”, though she “feels sad that I had to rush my children into growing up and becoming independent. But I think they’ve turned out OK.” She pauses. “I actually took them to the Bridgerton premiere at Tate Modern and it was the first time we’d ever done anything like that together. They’ve always seen their mother and ‘Polly Walker the actress’ as very different entities. But it was so lovely to see them enjoying it and celebrating our journey together as a family.”

‘Bridgerton’ is on Netflix now