One uncomfortable consequence of political longevity is seeing the facts prove some of one’s most confident forecasts wrong. As the trade secretary overseeing Britain’s entry into the single market in 1992, I claimed it would wonderfully boost our exports. As I outline in my new paper for Policy Exchange, I was proved wrong. Over our 28-year membership, British goods exports to the EU grew less than 1 per cent a year, while our exports to the 111 countries with which we had no trade deal grew four times as much – by 87 per cent.

Yet the present Business and Trade Secretary, Peter Kyle, is apparently ignorant of this disappointing experience. He has justified the government’s proposed ‘reset’ of relations with the EU by claiming that ‘the single market is where the magic happens’.

Why are Kyle and – to be fair – most of the political class unaware of the failure of Europe’s single market to live up to expectations? It must be because the single market was the one aspect of the EU which almost everyone across the political spectrum agreed was a ‘Good Thing’. Free market Conservatives welcomed it because it was supposed to unleash market forces; Eurosceptics were persuaded to support it because Margaret Thatcher advocated it. Labour and social democratic Europhiles were persuaded by former EU Commission chief Jacques Delors to back the EU single market as a way to regulate the market in the public interest – through European institutions. So no one bothered to look at how our exports had actually performed until very late in the day.