I heard on radio 4 (I think it was PM) that a reporter went on that train today. As far as he could tell, there are usually empty seats which Jeremy Corbyn could have found for him and his wife.
Re-nationalisation would be a disaster. During the past three days, I have been on SW Trains, Cross-country, East Midlands, London Midlands (I think) and observe many other trains at stations. It is amazing how many people are on all these trains at whatever time of day one is travelling. The Assisted Travel was excellent, the trains clean inside and out and the stations clean too.
(I went to basingstoke-Birmngham New St-Sheffield; Sheffield-Nottinghamn; Nottinghamn-Tamworth-Rugby-to get to Northampton; Northampton-Coventry and back home via Southampton.)