Boris Johnson, who is a current candidate to replace Theresa May as UK prime minister, refused to take part in a face-to-face meeting with US President Donald Trump, according to ITV's political editor.
Neither Trump nor Johnson commented on the reported incident yet.
The reports come after Trump had a 20-minute phone call with Boris Johnson earlier in the day.
President Donald Trump and First Lady Melania arrived in the United Kingdom on Monday for a three-day state visit, during which the president is expected to underscore the importance of the bilateral relationship between the two countries amid concerns over Brexit and the upcoming resignation of UK Prime Minister Theresa May.