I dunno. Easiest thing to do would have been to let him stay on the train till the next stop whereupon Auld Bill could have dealt with him (as Edukator said happens in France).
Big Man was silly to take it into his own hands – could have escalated into something far more serious had No Pay been up for the fight.
In the Summer of ’89, I travelled all over London and only ever paid when I was asked to or IIRC, you could buy a travelcard from a newsagent that would continue to work for around 3 or 4 days afterwards. Mind you, if I’d been asked to leave the train, I’d have just got up and gone, not refused.
If I could find a way of easily dodging fares now, I would. Hopefully, I’d manage it without bumping into any of the STW Hardman brigade.