Imports from inside and outside the EU moved roughly in parallel after the mid-1980s, but this close relationship fell apart at the end of 1992 when the arrival of the single market meant that trade within the EU had to be measured through VAT returns rather than customs declarations at borders.
Since that time imports from within and outside the EU have diverged. Excluding oil and erratic items, import volumes from outside the EU in the three months to October were 11 per cent higher than a year earlier, while intra-EU import volumes fell by 7.5 per cent.
The economists at UBS fear that imports from the EU have been underestimated by pounds 9bn in the first 10 months of the year. Importers may be trying to avoid VAT. But the Central Statistical Office rejects such a 'black hole'. It says goods brought into Britain via entrepots like Rotterdam are now recorded as imports from their original point of departure, not the Netherlands.
But the evidence for the CSO's explanation is not entirely convincing. True, imports from the Benelux in the first 10 months of 1993 were down pounds 50m on 1992, while imports from the rest of the EU were up pounds 283m. But these figures are not big enough to explain the entire divergence. Most of the black hole remains. Beware nasty surprises.