In message <bz4Aeb$JvwSIFwry@g52lk5g23lkgk3lk345g.invalid>, at 23:29:29 
on Sat, 7 Jun 2008, Mike Barnes  remarked:
>>Try the Regulation of Railways Act 1889, Paragraph 5(1):
>>
>>Every passenger by a railway shall, on request by an officer or servant
>>of a railway company, either produce, and if so requested deliver up, a
>>ticket showing that his fare is paid, or pay his fare from the place
>>whence he started, or give the officer or servant his name and address;
>>and in case of default shall be liable on summary conviction to a fine
>>not exceeding level 2 on the standard scale.
>
>So you are required to give up your ticket to an officer or servant on
>request. That seems to put you in a rather weak position for the rest of
>your journey.

This has already been covered earlier in the thread. They should give 
you a receipt. If the ticket remains valid (although it's not clear why 
they would keep a valid ticket) you should be able to use that receipt 
for travel [1] and if they say it isn't valid then it's common sense 
that you shouldn't be using it for onward travel. Although the receipt 
will assist you making your case against them afterwards if you think 
that opinion was erroneous.

[1] Although I agree that's not mentioned in the T&C unless such a 
receipt qualifies as a "ticket".

-- 
Roland Perry