And I see that you continue to talk in generalities, rather than addressing the specific points raised in this thread, editing out or failing to answer the specific questions asked, especially wrt a guards legal powers over passengers.
Before I upset all TOC employees, I do know 99% are lovely and sensible, but unfortunately as a passenger I have had a few bad experiences this year, the latest with Northern's untrained monkeys which are the subject of many complaints in another thread. Personally I'm fed up with TOCs/TOC employees/agents acting outside the law and/or being in breach of contract and I'm no longer prepared to sit supinely by as suggested in this thread, however unequal legal action may prove. If BTP are stupid enough to aid or abet illegal TOC actions, fine that's just more grist to the mill.
You asked the following question:
I'm certainly not getting into lengthy arguments here or discussing silly hypothetical arguments, but I'll repeat the points you haven't answered:
It was bb21 who raised the possibility of the BTP being called, I merely answered some of his questions. But yet again you've failed to answer my question. Are BTP untrained in the Byelaws? How can BTP take enforcement action under the byelaws if they are not aware of their provisions? I don't understand your point about the guard, surely the BTP are being called to deal with the passenger, who is also not breaching any bylaw and is seeing the railway break the contract between them?
This thread is about the validity of a ticket, a dispute between a traveller and a guard concerning that validity, whether another authorised person can overrule another and the likely outcome.
Unless an issue arises leading to an allegation of breach of National Railway Byelaw 6.1 (2005) any issue relating to validity of tickets in respect of the foregoing is covered by Byelaws 18 to 22 inclusive and the enforcement action to be taken, if any, will be dealt with by the TOC as explained in my response to your question.
If there is an allegation of bad behaviour by the guard, the detail of that allegation needs to be specified, it cannot be an allegation of breach of Byelaw in relation to ticket validity as the Guard is not the person using the ticket, and the matter will have to be investigated as the subject of a separate complaint to the TOC management.
I do not intend to respond on this thread further.