Musk is tall and broad-shouldered. His physical presence, wealth and reputation ought to make him intimidating. But he speaks in the calm, unthreatening, reflective, even hippyish cadences of Silicon Valley. His accent, like his first name, is neutral and unplaceable, as suits a man whose ambitions and activities are extraplanetary. He starts many of his sentences with ‘so’, as seems to be the fashion, and having built four billion-dollar businesses is comfortable with conspicuous understatement. “So I decided to do a couple of internet companies,” he says as he summarizes his early career, “and that worked out reasonably well.”

But things haven’t always gone his way. “It was like being in the stockade while people hurl shit at you,” Musk says of Tesla’s early days. “We struggled very badly for many years just to keep the company alive. I had nothing left. I had to borrow money for rent. I sold everything I could, and I would have sold the plane too except that in 2008 you literally could not sell a plane.”

The plane is a Dassault Falcon 900 intercontinental jet; there’s also a vast new Bel Air mansion. But he denies that he is materialistic: he points out that he is ‘a volunteer in all this’, and that if he had wanted bigger and safer returns on his capital he’d have invested in real estate, or oil. “Profit is important in that if you don’t make more money than you spend, eventually people will stop giving you money and your company will die. But it’s not something that’s of personal interest to me. I just want to have the resources to get the things done that I think matter.”