The argument in favour of national, democratic and political, control of parts of the economy is that decisions can and will be made on more than purely private profit grounds. Things such as the public interest can and will be considered too. The argument against national, democratic and political, control of parts of the economy is that decisions can and will be made on more than purely private profit grounds.

Which is how we get HS2:

The Treasury chief who initially signed off on funding for High Speed 2 has called for the £56 billion project to be scrapped, saying that it would fail a "rigorous cost-benefit analysis".

It fails even a reasonable one. The sums depend upon the value of time saved by the faster train set. Which is calculated by assuming that people on a train can do nothing other than be on the train waiting to arrive. The mobile phone, mobile internet, means that this is an incorrect assumption. The cost benefit test is failed purely on this point.

Lord Macpherson of Earl's Court, who was permanent secretary at the Treasury until 2016, said the rail scheme "always had a low economic return compared to other transport projects" and was based on technology that was likely to look obsolete by the time it is finished in the 2030s.

Quite so, it’s a 19th century technology about to be entirely overcome by the 21 st century one of the driverless car. Other than the baying mob chasing the contracts to do so there really is no good reason to build it.

So, obviously enough, we should stop doing so.