Earlier quoted context omitted.
I never understood why trains are so expensive in England: when I lived in Bristol I liked to spend time in Bath, it's just a ~10 minutes ride but it costed 10 pounds each way if I remember correctly... but at least you could bring your bike for free :p
Because the government decided to stop subsidising the railways. Everywhere you see very cheap train fares it's because they are subsidised.
As Boeing is finding out now with the 737 max and their Spirit subcontractor, every time you need to organise something across a contractual boundary, like who's responsible for making sure the doors don't fall off your aeroplane, it adds a lot of cost and time in contract negotiations, paperwork, inspections and inflexibility if you want to enforce what you have asked the other party to do and to understand what still remains your responsibility. Therefore when you go to a subcontractor for something you try to make sure it is very clearly defined what they are responsible for. For example, when an architect designs a skyscraper, they will try to design the cladding in a way that makes sure that watertightness is solely the responsibility of the one cladding subcontractor. If it leaks they are on the hook, simple. If you create complicated interfaces between systems then subcontractors can get out of responsibility for problems by blaming each other or the design of the interface.
So back to the railways. The government specifies where, when and how many seats a train service should have, they let contracts to train operating companies who then pay another (now government owned after it went bankrupt) company, Network Rail, to access the track. These train operating companies don't own the trains, they lease them from one of three other government created private (and now highly profitable) companies that provide all rolling stock. The train operating companies are generally responsible for light maintenance while the leasing companies are responsible for heavy maintenance. The train operating companies also provide staff for stations and branding but they don't own or maintain the stations although they are responsible for some maintenance and keeping them clean (or they used to be, it's complicated). All the money for this comes from the government as subsidy and from fare revenue paid to the train operating companies through a central clearing house. Train fares are for the most part dictated by government. Train operating companies have a little bit of freedom to sell discounted tickets to fill spare capacity, but there isn't really any on our main intercity routes and on commuter routes when people need to travel so most people are paying the government capped fares.
Here's an example of why this system is crazy. If we want to upgrade a rail line to electronic moving block signalling to increase the number of trains that can run per hour there are negotiations between the department of transport, the track owner, all the train operating companies that run on that route and their leasing companies about who is paying for the equipment to be fitted to the track and the trains, the specification to make it all compatible, when this will happen and who is responsible if things go wrong. On a complicated route like the West Coast mainline, this could involve multiparty negotiations between say 10 operators, 4 leasing companies, network rail and the department of transport. It could involve hardware and software modifications to more than 20 different types of train, some of which are up to 40 years old. Guess who is actually paying for all this anyway? The taxpayer and government dictated fares from rail passengers. There is no real free market incentive operating anywhere here to drive cost efficiencies in providing these modifications and all these negotiations need to be documented, have responsibility assigned and have procedures agreed. Guess who you need to do this? Lots of corporate lawyers... Guess how long this takes, fucking ages.
That is why we have a system where a ~350 mile journey from London to Glasgow takes more than twice as long and typically costs more than twice as much for half the legroom compared to a ~350 mile journey from Paris to Bordeaux.
A train network is like the mechanism of a clock, the trains are like the teeth on the cogs; they have a place they should be and they need to move in sync with perfectly with each other. We've designed a system that makes organising this insanely complicated with no overall coordinated strategy for improvements. A densely populated country like ours can't function properly without an efficient train network to allow its workforce to be flexible and move around easily and it affects our productivity and our ability to remain competitive globally.
Edit: corrected missing word