Foreign Secretary Dominic Raab is in Washington where he is expected to try to reassure US politicians about the latest Brexit twist.
Some US politicians are concerned about the UK government’s plan to override parts of the Brexit divorce deal.
Mr Raab will meet US Speaker Nancy Pelosi, who last week said there would be no UK-US trade deal if the Northern Ireland peace agreement was undermined.
No 10 has said the peace agreement will be upheld in all circumstances.
Mr Raab is due to meet leading politicians including his US counterpart, Mike Pompeo, as well as Democratic Congresswoman Ms Pelosi, who is speaker of the House of Representatives.
Threats over UK-US trade deal
Brexit is expected to be high on the agenda at the Washington meetings.
Earlier this week,