A year ago this week, when he completed the purchase of Twitter for $44bn, Elon Musk tweeted “the bird is freed”. Billionaires like nothing more than casting themselves as popular liberators, but the acquisition fitted the pattern of his ever-expanding empire.

Musk has colonised areas of the economy from which public funding and regulation have been in retreat. His carmaker, Tesla, is shaping the future of transport; SpaceX, meanwhile, has in many ways replaced Nasa on the final frontier (so far this year it has launched 75 spacecraft). READ MORE