I'm not one to support a Tory, but on this occasion I might just a little bit. Apparently, MPs get expenses to travel second class but can't submit first class for reimbursement now. He and three or four in his group, who had already got their return second class tickets, got on a different train because of a diary change, so had no seat in second class, went to first with his aide, having separated from his security people, and awaited the inevitable inspector. The ITV person (who was in another carriage altogether) who tweeted about the situation may have seen an opportunity to take a rise out of him, and one tweet to Tony Morris, Granada TV news presenter, refers to this reporter 'prepping the inspector for a scrap.'
I don't defend what may have ensued in terms of alleged arguments, but I get the impression this has been blown out of proportion. I have got on many a London train and found someone in my, or a colleague's, second class seat because they missed their own train or didn't want to wait for their later train. The Picadilly to Euston rush hour trains are a nightmare. People with no seat rush to First class and sit there, hoping seats will become available before the inspector comes along. Most inspectors understand the situation and will give passengers an opportunity to move if a vacant seat has come available back in second class, so the 'arguing' referred to may have been no more than discussion about whether he could move or pay the upgrade.
It's a judgement call - do you get off the train and start all over again, hope to spot a vacant seat in due course, get a seat in first class and stand the difference yourself?