Liam Fox is tired of talking about Brexit. The time has come, he says, to “try to get our perspective back”.

The international trade secretary, whose job it is to boost British business around the world, has spent the two years since the European Union referendum contemplating life outside the bloc. Suddenly, however, the threat of a trade war has brought a new danger to post-Brexit plans.

Just as Britain prepares to take back control of its trade policy for the first time in more than four decades, tensions are riding high on the global stage. With the United States, China and the EU at loggerheads, President Trump has shown that he is prepared to hit America’s closest allies with tariffs. Even Dr Fox, a