LONDON -- Former German Chancellor Helmut Kohl often used to say the euro would only work properly if and when Europe had a full political union -- in other words if there was a single government for Europe with a large central budget. He was, of course, completely right, and this explains why the British are still saying "not yet" to the euro-zone.

The decision has been dressed up in all sorts of economic jargon. Five enormously elaborate tests have been paraded by the British Treasury, purporting to demonstrate whether joining would be in the British national interest. They claim to "prove" that the time is not quite ripe but may be in a year's time, when the finance minister, Gordon Brown, will have another look at the situation.

These tests are mostly highly technical and include all sorts of subjects like the possible effect on inward investment. Treasury officials claim to have consulted Japanese business leaders to see how they feel about the issue. And their economic advisers make all sorts of speculative and ambiguous predictions about future gains and losses, all dressed up in pseudo-scientific economic jargon.