The job spec pretty much writes itself. A tough negotiator. Fluent in lots of languages. Good at lots of nit-picky detail. Works well under pressure. Available to start the day before yesterday. Salary – name it yourself.

The head-hunters are no doubt already scouring the world for experienced and wily trade experts who can start hammering out the dozens of potential new agreements we can strike now that we are heading out of the EU. But what principles should guide them as they start that mammoth task?

It is four decades now since the UK last needed any trade negotiators of its own. As soon as we joined the EU, we handed that responsibility over to Brussels. There are, of course, some British experts, but they have all been working for the Commission rather than Whitehall.

We don’t yet know when we will finally leave the EU, or the precise terms of our exit. But one thing is certain. We will certainly be able to negotiate our own treaties again. Even the Swiss, with access to the Single Market, do that. They have a very successful agreement with China that has seen exports to that vast market quadruple in the past decade. The hiring has already started – and since Canada has 300, and the EU 600, these will be big teams.