There are two foreseeable circumstances where a member of TOC staff/contractors would have a power to detain a passenger.
1) Regulation of Railways Act
The first example would be under section 5(2) of the Regulation of Railways Act 1889 (RoRA), as
@styles referenced above. This is often referred to as the 'three fails' because it is engaged if a passenger fails or refuses to either:
- show (and hand over) a ticket, or
- pay their fare, or
- give their name and address
It is only if the passenger fails/refuses to do ALL three that they can be detained. The OP in the
thread here (which I imagine gave rise to this thread) offered to pay for a new ticket, and gave their name and address. Therefore they met two of the three requirements - so the RPIs did not have any power to detain them under RoRA.
RoRA also doesn't give staff the power to detain merely because they
suspect that a passenger has given false details, or because they want to verify the details given. There would need to be a separate power for this to be the case - no such power exists under RoRA. Of course,
section 24 of the Police and Criminal Evidence Act 1984 (PACE) gives
police officers the power to arrest someone they suspect of committing a summary-only offence (such as giving false details under section 5(3)(c) of RoRA) - but that power does not extend to TOC staff.
2) Citizen's arrest
The other situation would be under
section 24A of PACE - the so-called "citizen's arrest" that any member of the public has. But this only applies to
indictable offences, whereas all of the relevant RoRA offences are summary-only. Therefore it would take a more serious offence, like suspected fraud or assault, for this power of arrest/detention to be engaged.
So in essence, staff such as RPIs only have the power to detain ticketless passengers who refuse to pay AND refuse to give a name and address. Those offering to pay and/or who give a name and address (even if it cannot be verified) cannot be detained. Detaining a passenger under such circumstances could amount to false imprisonment, which is a criminal offence for which quite substantial civil damages are available. That's not to say that staff can't call the police, or
request ID or other proof of identity. But they have no right to detain someone in such circumstances whilst waiting for the police, and they have no power to force the passenger to produce proof of identity.
Layered on top of that, many TOCs will have policies which prohibit their staff from detaining passengers at all (even if it would be lawful). But failure to abide by such policies would remain a disciplinary matter between the staff and their employer, rather than something that would give an affected member of the public legal recourse. They could raise a complaint about it of course, but if the detention was lawful, any outcome would be a question of customer service and goodwill rather than legal entitlement.
Where there could be more recourse is a potential breach of the GDPR, if RPIs are inappropriately noting personal data like banking app details or failing to provide the details that the GDPR requires (e.g. the purpose for data processing). I'm sure TOCs' Data Protection Officers would be having kittens if they knew the antics some RPIs get up to!
If the RPI is not satisfied your details are legitimate, they may suspect you of committing the separate offence of failing to provide your details. This is a legal obligation you have, although the fact you aren't on the electoral roll or credit register would not, in my view, be enough to warrant suspicion. However, either way, RPIs, if dissatisfied with your credentials, are entitled to call the police, who have extra powers to ascertain them from you.
It's fairly irrelevant whether or not an RPI has suspicions - at the end of the day they can call the police, but they can't detain you until they arrive.