Rail subsidy per person
UK: €64
France: €203
Germany: €209
The UK makes a conscious decision not to subsidise its rail network to the extent of France and Germany. I'd rather we had spent the last 40 years building high speed lines, but as a country we didn't want that.
My list would be
* HS2 as now planned, extended up the east coast to Edinburgh, Glasgow and Aberdeen
* Plymouth -> Exeter -> Bristol -> Birmingham -> Cambridge -> Norwich
* Swansea->Cardiff->Bristol->London
* Liverpool-Manchester-Leeds-Hull
With junctions to allow services to run as appropriate for demand (e.g. Swansea-Cardiff-Bristol-Birmingham once an hour, continuing to Manchester or Leeds, Swansea-Cardiff-Bristol-London twice an hour, Liverpool-Manchester-Leeds-Newcastle-Edinburgh, etc)
Had we done that we'd have the capacity to offer cut price, but alas we didn't.
As it stands, trains - especially cross country ones - are massively crowded even with the price as high as it is, because people prefer to take a dog-slow overcrowded train from Reading to Manchester, rather than to take a cheaper coach.