Paul Terry wrote:
In message , Richard J.
writes

Baker Street this afternoon, eastbound Circle line. Judging by how
long I waited and the number of people on the platform when I got
there, I reckon there was a 10-minute gap in the service. Nothing
exceptional about that, though it should have been 4-5 minutes.

Why do you think that the circle line runs at 4-5 minute intervals?

The platform in question is served by both the Circle and Hammersmith & City
lines. Each is timetabled to run at 8.5 minute intervals, giving a combined
service interval of 4 to 5 minutes.
--
Richard J.
(to e-mail me, swap uk and yon in address)