Do you watch a lot of period drama? I don’t, generally, but as it happens I have watched several hours’ worth this weekend, and I have noticed that there is a way people talk in (most) period drama which has nothing to do with the script: a mannered, diffident style which seems to transcend both character and chronology, so that it doesn’t matter if it’s rural Edwardian England (hello, The Woman In Black!) or 1950s London (howdy, Call The Midwife!) or – well, frankly, I have no real idea when Upstairs Downstairs, currently playing at a screen near me, is set, nor where, but everyone is speaking that way.

It wasn’t always like this. Nobody speaks that way in Room With A View, nor even in the 1990s TV adaptation of Pride and Prejudice. It seems to have sprung up since the early 2000s, which leads me to suspect it’s probably mostly Keira Knightley’s fault.