Recep Tayyip Erdogan, Turkey’s autocratic president, is painfully learning a lesson supposedly taught by King Canute, 11th century king of England. The latter, it was said, sat in front of the incoming tide, to teach his sycophantic courtiers that he did not rule the seas.

Mr Erdogan is learning, similarly, that the tides of global finance will not do what he tells them to do. A wise ruler has to change policies. The decision to raise interest rates was the right one. He might have to go further still.

The financial tide has been flowing against many emerging economies, as the dollar has strengthened. But the Turkish lira has been swept furthest out to sea. The currency fell to almost TL5 to the dollar on Wednesday. That would have amounted to a depreciation of almost 20 per cent since the end of April. That would risk an upsurge in inflation, thereby threatening the relatively low inflation — by Turkey’s historical standards, at least — enjoyed by the country, under Mr Erdogan’s rule, since 2004. If the slide in the currency were unabated, the inflationary upsurge might bring back the bad old days of the pre-2001 era.