Garry Smith wrote:
On both Tuesday and Wednesday this week, KX St P Underground
station has been closed temporarily at around 1830, due to overcrowding.

I've only in the last few weeks returned to working in London, so I
don't know how common this is nowadays. But these are the first
occurrences of closures that I have been aware of.

How often does this happen?

Too often, even before all the new stuff at St Pancras.pen?
--
Michael Hoffman