Perhaps as early as tomorrow, the prime minister will press the button and launch Article 50 on its inexorable, ballistic trajectory towards impact in March 2019. From the political class here, let alone in Brussels, comes incessant pessimism about those two years: it will be fractious, we are not ready to negotiate, a trade agreement is all but impossible, the timetable is too tight, we’re going over a cliff.

This is mostly wishful thinking by those who want us to fail. A conversation last week with Tony Abbott, the former Australian prime minister, brought this home to me. When he became prime minister, Mr Abbott did something unusual. Noticing that his country’s trade negotiators had spent years meandering towards deals with China, Japan and other