Important businesses are losing patience with the UK government over progress — or rather lack of it — in the Brexit negotiations. With just 10 months to go before Britain leaves the EU, that is entirely comprehensible. Airbus, for example, has threatened it might pull out of the UK altogether if no trade deal were agreed. Amazingly, Jeremy Hunt, health secretary, responded that it was “completely inappropriate for businesses to be making those kind of threats”. Is this the “party of business”?

Rival politicians are competing for the favour of their base. But some actually believe a “no deal” Brexit is a credible option, possibly even an attractive one. For support, they can appeal to Economists for Free Trade. While theirs is a minority position among economists, it must be evaluated, not only because some members are reputable, but also because it is influential in Brexiter circles. Two recent papers — Alternative Brexit Economic Analysis and What if We Can’t Agree? — lay out the group’s arguments for the superiority of a clean break over remaining inside the customs union and single market.

There has been an extensive debate about the best economic models to use. In recent work, this group simply argues that “if the correct Brexit policies are fed in, it seems that all of the models produce directionally the same results — all clustered around a positive 2 per cent to 4 per cent of GDP range” from unilateral free trade, under World Trade Organization rules. Yet such results are the opposite of those of almost all other economists. The differences are due to varying assumptions, as Alasdair Smith of Sussex University told the House of Commons Treasury and International Trade Committees’ joint inquiry in May.