Come 1 November, when the Air Passenger Duty is introduced, Britain's airports are likely to become a notch more chaotic as rows break out about how much tax should be paid. A fortnight ago, I wrote about the confusion surrounding the levy. The rule seems simple enough: a flight to a destination within the EU incurs a tax of pounds 5, while flying farther afield costs pounds 10. But no one seems sure how the rule applies to people changing planes en route.

Now Neil Taylor, of Regent Holidays in Bristol, writes to add an extra tangle or two. In the case of Switzerland, for example, 'the tax to Bern and Zurich is pounds 10, as you'd expect for a non-EU nation. But Basle and Geneva airports are, for the purposes of the tax, regarded as being inside the EU - so you only pay pounds 5.'

Sudden changes can also be anticipated for new year's day if, as expected, the Scandinavian nations and Austria join the EU. Austrian Airlines is charging pounds 10 until 1 January, pounds 5 thereafter - even for destinations beyond the Union. The Scandinavian carrier SAS is sticking at pounds 10 for all destinations outside Europe. Luckily, Liechtenstein, whose exact status vis-a-vis the EU is deeply obscure, has no airport.