The US may finally have shown Boris Johnson the consequences of Brexit

Editorial: Speaker Nancy Pelosi has warned the PM that if he does tear up the Brexit deal, he also shreds his chances of winning a free trade deal with the United States

Nancy Pelosi has reminded the prime minister that his threatened actions over the Northern Ireland protocol carry additional risks (AP)

Even someone as complacent and blindly optimistic about Brexit as the prime minister must realise that he now has to deal with disquiet in Washington, as well as resistance in Brussels, Paris, Berlin and Dublin, in his attempt to renegotiate his Brexit deal.

When Boris Johnson met Joe Biden for talks last September, the prime minister emerged from their meeting muttering that “Joe has a lot of fish to fry”. It sounded like a bruising discussion.

Just in case the prime minister is suffering from one of his occasional bouts of wishful thinking, though, Nancy Pelosi – speaker of the US House of Representatives – has chosen this moment to remind him that if he does tear up the Brexit deal, then he also shreds his chances of winning a free trade deal with the United States.