The Scandinavian prime minister Erna Solberg said yesterday that she was ready to negotiate in any policy areas left outside the final agreement between the EU and Britain.

She said she hoped the British would stay “close to the single market”.

“That will be the easiest way to work together in the future,” she told Reuters.

Solberg added: “If not we are prepared to negotiate in all of the areas.

“We feel we have a good cooperation both with Britain and the EU.”

Although the oil-wealthy country is not part of the EU, it belongs to the single European market.

UK Theresa May has estimated the UK’s payment to the EU as it leaves the bloc to be £35-£39bn.

The UK treasury committee chair Nick Morgan has asked the National Audit Office to probe the government’s Brexit withdrawal payment.

The UK voted to leave the EU on 23 June 2016.