Any acceptable solution to the grave refugee crisis that is preoccupying the governments of Europe will require the full cooperation of Turkey. Yet the Turkish Government seems willing to trade that cooperation only in return for concessions to other Turkish demands that have no connection with the refugee issue.

Some parts of the European media have even interpreted that as Turkish blackmail. One suggestion is that the European Union should lift visa restrictions on Turkish travellers to Europe, in return for Turkey agreeing to take back those migrants without a genuine claim to political asylum who have crossed the Aegean Sea to Greece. In fact most are Syrian, and will have such a claim. Turkey has so far only agreed that Nato vessels – including from Britain – can operate against migrant smugglers in Turkish territorial waters. Greece has a similar arrangement.