wrote in message
.uk...
I have sat in first class on a long distance train with a standard class
ticket with the aim to upgrade, and none of the crews have ever tried to
penalise me.

Different rules apply in Penalty Fares areas.

You're correct that elsewhere on National Rail, unless you're using a Season
Ticket, there's no penalty for asking for an upgrade in 1st Class from an
ordinary walk-on Standard ticket beyond the appropriate difference in fares.
That being said, the fares structure nowadays is so convoluted that - except
for an upgrade to Weekend First - it might be quite difficult working out
what you'd actually end up being asked to pay.

--
Walter Mann