Superphil
Dismember
France, Italy, Germany, Spain has lots of space to build new high speed lines. We have to make do with existing lines which costs hundreds of millions to maintain.
As an example, I hadn't been to Naples for at least 10 years. When I went last Summer they had built a new station and high speed line all the way to Rome and beyond to Milan which serves the Freccia Rossa.
By the time we do get a proper high speed line serving the whole country, like we have from the channel tunnel to London, train technology would have moved on.
There’s plenty of room to build a new line along the side of the M23/A23, tunnels can be dug quite competently nowadays too (Gotthard Base Tunnel, Crossrail, etc.) there are opportunities to continue into London, but there are also plenty of people who are influential enough to make sure it doesn’t happen. And shareholders of the vested organisations who’d not want to see their dividends (mostly in Euros) spent on rail improvement.
As has been said, this country voted last month to carry on with the current system, not a lot the rest of us can do about it now)