In message , at 10:05:26 on Sun, 23 Dec
2012, Roland Perry remarked:
"And standing" normally means at most one extra passenger per row of
seats, so 25% over capacity.

Mush more than that, you've forgotten the vestibules (although there
have been cases reported of Virgin clearing them) and people standing
next to non-seating areas like toilets and luggage racks. I've also
travelled sat in the luggage racks, and the area outside the disabled
tiolets is quite large.

This morning at Ely the trains heading for the Midlands were so
over-full that people with reservations on the train were left on the
platform because they literally couldn't get on board at all. I've seen
the same on the first train (late morning on a Sunday) from the Midlands
towards Stansted.

The 170's on that route have 1/3-2/3 doors and quite big vestibules
which can take a couple of dozen each at a pinch, although normally much
of the space is taken up by baggage.
--
Roland Perry