the issue is overcrowding. i'm in commuter country and the trains to london in the morning are horrific. you're standing shoulder to shoulder for the journey, every day there is at least one cancellation or delay due to signal failure, shortage of crew, etc which pushes more people onto fewer trains along the network... people complain about fares, and the government wants to lower them, but if the fares are lower more people will use rail. without an increase in capacity lower fares and rising population will turn rail into india level. already tfl travel at rush hour is like the tokyo meme. i can't live in london because the rents are too high.  all that being said rail and metro is not that bad in the uk compared to most other european countries, it's quite good in comparison actually.
United Kingdom