Reliability of trains in the UK really varies by route. When I was studying and when I first started working I extensively used mainline routes and had no issue

Reliability of trains in the UK really varies by route. When I was studying and when I first started working I extensively used mainline routes and had no issues. The last train I could take on a Friday night was 10pm, but given it was a 3 hour journey that didn't seem unreasonable. Each year there was usually one incident that caused delays, but other than they worked well. If I took a fast train the journey time was around the same as driving - quicker in fact given on the journey I would stop for a break - and ticket prices were about the same as driving (for 1 person). On the other hand I was working in London in 2018, and at weekends often flying from LTN. In the end I added an hour buffer (to a 45 minute journey) because the reliability of Thameslink was so bad.