Boris Johnson and U.S. President Donald Trump meet at the UN headquarters in New York on September 18, 2017 Brendan Smialowski | AFP | Getty Images

U.K. Prime Minister Boris Johnson has defended his newly-negotiated Brexit deal after criticism from President Donald Trump. In an interview with Nigel Farage, the leader of the U.K.'s Brexit Party, on Thursday evening, the president said the scope of a trade deal with the U.K. would be limited under Johnson's proposed divorce agreement he recently sealed with Brussels. The deal was also approved, in principle, by U.K. lawmakers last week but political wrangling in Westminster has led to the U.K. leader pausing his Brexit bill and opposition parties agreeing to an election. Brexit is now scheduled to go ahead on January 31 next year, although Britain could leave the EU earlier if the bill finally makes it through both chambers of the U.K. Parliament at an earlier date.

"We want to do trade with the U.K. and they want to do trade with us, (but) to be honest under certain aspects of the deal, you can't do it," Trump said in the radio interview on Thursday. "We can't make a trade deal with the U.K., and we can do many times the numbers we're doing now and certainly much bigger numbers than you're doing under the European Union. Your trade with us could be four to five times higher than it is right now — that would make your country much bigger economically, (but) you're being held back by the European Union." Responding to Trump's claims, a spokesperson for the prime minister's office told the BBC that Johnson's Brexit deal "ensures that we take back control of our laws, trade, borders and money." "We know the deal enables us to secure deals with a range of growing economies (and) we'll be setting out to do that," he said, adding that talks with U.S. officials about a trade deal had so far been positive.

At the G-7 summit in August, Trump said the U.S. was going to do "a very big trade deal" with the U.K. post-Brexit, after promising a "phenomenal" deal on his state visit to Britain in June. The U.S. currently has a trade surplus with the U.K., according to the Office of the U.S. Trade Representative, with exports to Britain at $141.1 billion and imports from the country at $121.2 billion.

Interference allegations

During Thursday's interview, the U.S. president also criticized Jeremy Corbyn, leader of the U.K.'s Labour party and the main opposition to Johnson's Conservatives. "Corbyn would be so bad for your country, he'd be so bad, he'd take you in such a bad way," he told Farage. "He'd take you into such bad places. But your country has such tremendous potential, it's a great country." Trump's comments were later slammed by Corbyn, who took to Twitter to respond to the claims. "Donald Trump is trying to interfere in Britain's election to get his friend Boris Johnson elected," he said.