This looks familiar ...

I saw this scene being filmed in at St Pancras station last year! At the time, the security guard said it was for a "BBC drama that's a bit like Downton Abbey". Wondered if it was Parade's End when I saw all the the reviews, and sure enough, this was the opening scene.

(Thought I'd blipped the filming, but can't find it in the archives - must have gone for a different shot instead.)