In 1998, the EU 15-country Single Market imported (from outside the EU) merchandise worth $801 billion. This was less than the amount imported from round the world (including from the EU) by the USA ($944 billion) but almost three times as much as the amount imported by Japan ($281 billion).

In fact, the Single Market, with a low average external tariff and almost no quotas, is an economy which is pretty open to imports.

So open that, over the period 1992 to 1998, the USA, from outside the Single Market, increased its merchandise exports into the Single Market at a faster rate than the UK, which is inside the Single Market. Total US merchandise exports to the EU are now bigger than the UK’s.

despite the UK’s geographical proximity to mainland Europe and the wondrous "benefits" of being "in" the Single Market.

Part of the explanation for American success could be that firms based over there actually pay a LOWER average tariff for the privilege of exporting to the EU than the effective tariff the UK pays to Brussels for the privilege of exporting to the EU.

In 1998, the EU’s average industrial tariff on imports from outside the EU was 3.6%. In that same year, the effective industrial tariff paid by the UK to Brussels through the mechanism of the EU Budget was 5.7%.

The effective tariff UK plc paid to Brussels was therefore almost 60% higher than the actual tariff borne by USA Inc.

If corporate UK withdrew from the EU and exported to the Single Market from outside, it would be

almost 37% better off than it is at present. True, it would have to pay a tariff of 3.6% to get into the Single Market. But corporate UK would benefit from savings equivalent to 5.7%, which the UK exchequer would no longer have to hand over to Brussels and which would be available to be passed on to UK businesses and individuals as tax reductions, resulting in lower ex-factory costs and higher domestic demand.

The gains would not stop there. Once EU withdrawal had taken place, the UK would be free to negotiate bilateral tariff-free arrangements with the USA, with her other traditional trading partners and, of course, with the remaining EU countries, who need the British market far more than Britain needs theirs. All this would result in further reductions in costs, not just for UK exporters but for UK importers as well.

The economic logic is compelling. Eventually, the political logic will become equally compelling.