For Finland and Sweden to join Nato, all 30 existing members must say yes. But for now, one is saying no.

President Erdogan says he won’t agree to admit countries which apply sanctions on Turkey.

Sweden suspended arms sales to Turkey three years ago, following Ankara’s military intervention in Syria. And according to the official Turkish news agency, both Finland and Sweden have rejected dozens of requests to extradite Kurdish militants who Turkey describes as terrorists.

Both countries are sending delegations to Ankara to try and solve the problem, but President Erdogan says they shouldn’t bother.

He seems determined to extract a price for his precious vote. On Sunday, the US Secretary of State Antony Blinken said he was confident that Finland and Sweden would both join, despite Turkish objections.

The issue is likely to dominate discussions between Mr Blinken and his Turkish opposite number in Washington on Wednesday.

Having encouraged the two Nordic countries to apply, Washington won’t want to let them down at the 11th hour.