What is under threat is our mantle as the best place to do business from. London the trading post, the exporter of services and goods, is under threat. It is why the Mayor, Sadiq Khan, has already held out the hope that the UK can remain in the single market even if it is no longer in the EU. It would be possible, if we contributed a reduced sum to Brussels coffers, to strike a deal, on free movement of labour that allowed people with a firm job offer into the country. That might not square with the Brexiteers’ pledge to “take back control” but we must make sure that talent can flow in and ideas can flow out just as they always have.