LONDON (Reuters) - Irish Prime Minister Micheal Martin said on Thursday that U.S. President-elect Joe Biden wanted Britain to reach a Brexit trade deal with the European Union, so Prime Minister Boris Johnson should knuckle down to securing one.Biden’s win in the U.S. presidential election has changed the international context of Brexit: U.S. President Donald Trump backed Britain’s decision to leave the EU, while Biden served as vice president under Barack Obama, who advised against it. Biden, who is proud of his Irish heritage, has repeatedly said the U.S.-brokered 1998 “Good Friday” peace deal for Northern Ireland must not be undermined. That has been seen as a warning against a bill proposed by Johnson that would negate parts of Britain’s EU divorce agreement governing the UK-Ireland border. Biden repeated his support for the Good Friday agreement in a phone call with Johnson on Tuesday, and has previously said that if Britain undermines the pact, it will not be able to obtain a trade deal with the United States.