Biden arrives with demand that UK settle Brexit row over Northern Ireland

Warnings from envoys that David Frost must compromise with EU on border checks as risk to Good Friday agreement will not be welcomed by the US'

Senior US embassy diplomats in London, backed by the US national security adviser, Jake Sullivan, have directly warned the UK's Brexit negotiator, Lord Frost, that he will inflame tensions in Northern Ireland if he does not compromise over border checks.

A meeting between the US charge d'affaires Yael Lampert, currently America's most senior diplomat in London, and Frost led to an urging by the US for Britain to come to a negotiated settlement with the EU, according to an internal UK government note.