Boris Johnson mounted a charm offensive on Mr Biden during his first visit to the White House as PM - but looks doomed to come away empty handed on the trade front.
The US President offered Mr Johnson no encouragement on talks of a trade agreement between the two countries, warning: 'We're going to have to work that through.
The lukewarm message came amid claims from senior government figures that the UK is looking at joining the United States-Mexico-Canada Agreement as an apparent back door into American markets that could leave British goods ranked alongside Mexican and Canadian exports.
The Prime Minister previously told reporters in Manhattan there were plenty of reasons to be optimistic about getting a free trade agreement with the US, but faced a frosty relationship as the pair met at the historic White House event.
Mr Biden, who has strong Irish ties, made clear his concern that Brexit wrangling over Ulster's trade rules could undermine the peace process, insisting he feels very strongly on issues surrounding the Northern Ireland Protocol.
However, there seemed little prospect of Mr Johnson getting his dearest wish of a trade deal from Mr Biden. 'We are going to talk about trade a little bit today and we're going to have to work that through,' the President commented vaguely.
After Mr Johnson welcomed great progress with the ban on British beef imports already having gone, the President went on to note: And we're going to be working on lamb, too, in a possible boost to post-Brexit US-UK trade.
Speaking at the White House, the pair both enthused about the need for more action to tackle climate change, following the US announcement of a major boost in funding earlier.
Mr Biden also moved to reassure the UK that the case of Harry Dunn - who died in a road crash involving US diplomat Anne Sacoolas - is 'being worked on' as it was revealed yesterday that his family and Ms Sacoolas' lawyers had come to a 'compromise' in their civil lawsuit.
Trade talks between the two nations appear to be deadlocked, despite early promises and positive steps being taken by both sides. One senior government source signaled there were a 'variety of different ways' the UK could join the US-Canada-Mexico (USMCA) deal.