So Elon Musk has revealed details of his "Hyperloop" concept and I'm quite impressed with the concept...

The Hyperloop would consist of aluminum pods inside a set of two steel tubes, one for each direction of travel. These are connected at each terminus. The tubes would be positioned on top of pylons spaced 100 feet apart holding the tube 20 feet in the air, and the tube would be covered by solar arrays to generate its own power.

Inside the tubes, the pods would carry people up to 760 miles per hour. The pods would each carry 28 passengers, departing every two minutes from either location (or every 30 seconds at peak times). So each pod would have about 23 miles between one another while traversing the tube. The transport capacity would therefore be about 840 passengers per hour.
Hyperloop—a theoretical, 760 mph transit system made of sun, air, and magnets | Ars Technica

I think the UK government should reconsider HS2 and install a Hyperloop system instead. :-)