I have noticed that on many Virgin Trains that the first first class coach is often declassified, so you can get extra space for free.
If the service is busy and you think people will be standing just go and sit in an unreserved seat in First Class. It is very likely you will get to stay there for free.
If the service is busy and you think people will be standing just go and sit in an unreserved seat in First Class. It is very likely you will get to stay there for free.