Britain and Germany have been here before. The precedent, as Gordon Brown knows all too well, is scarcely encouraging. The last time a senior German official publicly criticised Britain’s economic policy, the spat sent sterling tumbling and ruined the reputation of the then Conservative government.

This week’s outspoken attack on Mr Brown’s strategy by Peer Steinbrück, the German finance minister, was as potentially damaging as it was undiplomatic. The pound, after all, has been sliding fast on foreign exchange markets. It is worth nearly a quarter less against the euro than a year or so ago. Some predict it is heading for parity.