Boris Johnson’s plans to tear up post-Brexit arrangements for Northern Ireland have come under fierce attack from Washington, with senior congressmen on both sides of the US political divide warning the “irresponsible” move is a threat to peace in the province.

Touring musicians and road crews have been “betrayed” by the government in the Brexit trade deal, the Lords has been told.

“We now face the most momentous peacetime decision,” said Heseltine, as Lords hand government their second Brexit bill defeat.