Besides the points all the other commenters made, there is an issue of congestion. Trains and train tracks in the UK are _massively_ over-capacity. The West Co

Besides the points all the other commenters made, there is an issue of congestion. Trains and train tracks in the UK are _massively_ over-capacity. The West Coast Main Line, which is the main connection point between London and most of the Midlands and the North is the most congested train track in Europe. Trains in the UK are expensive because we are decades behind in rail infrastructure spending while airports were targets of massive spending thanks to the boom in international low-cost flights in the 2000s and 2010s. HS2 should make train prices slightly more palpable, and hopefully more projects will follow. Also, advance open-return tickets bought 24h in advance are massively cheaper than tickets last-minute tickets.