"Matthew P Jones" wrote

He advised we were to Terminate at
Watford as all trains were, but we had to wait to get into the station.
I was making my plan to get to Watford Met as the train moved from the
fast to the slow and went into Watford, everyone stood up to get off,
but the driver said he had been given the all clear and we then shot on
at line speed to Euston. Our train was not full, there were two Virgin
trains at Watford and many people on platform 9 which we passed, I bet
they were "please" we did not stop to pick them up, I know I would have
been annoyed, especially as we slowed right down to go through Watford

What you couldn't have known is whether there were full trains behind yours
booked fast to Euston, whose passengers would not have been pleased to have
to stop behind yours while it picked up at Watford, or trains close behind
yours booked to call at Watford which could equally well pick up passengers
off terminated trains.

Peter