Hammond had been slated to appear alongside the prime ministers of Ireland, the Netherlands and Poland at a discussion over the future of Europe.

A spokesman for Prime Minister Theresa May said the guest list was published before Hammond had confirmed his attendance.

The finance ministry said in a statement:"He has accommodated as many speaking requests as possible in the short time available."

The Financial Times, which first reported Hammond's absence from the event, said it would have involved tough questions around the Irish border - a major issue for British lawmakers who have yet to agree a Brexit plan.

(Reporting by Andy Bruce; editing by Stephen Addison)