Colin wrote:

I thought that LUL were scare mongering a bit by telling people they had to
have their journeys complete by 6.30pm.

They were probably being cautious, because trains were in fact running
later than that. I got to Regents Park station at about 2015, where
there was a notice saying that the last southbound train would be at
2032 (I didn't notice the time of the last northbound). About a minute
after I got to the platform a train arrived, almost empty; there were
only 3 or 4 people in the leading car. The position wasn't much
different when I got out at Charing Cross.

--
John Ray, London UK.