The alliance between the US and the UK should be known as the “indestructible relationship”, Boris Johnson has told the BBC after meeting US President Joe Biden for the first time.
He said he had “terrific” talks with Mr Biden, who has travelled to Cornwall for the G7 summit of world leaders.
The summit begins later, with vaccines and climate change on the agenda.
Mr Johnson insisted the US president had not rebuked him over post-Brexit tensions in Northern Ireland.
However, Mr Biden is said to have “deep concern” over the situation.
The prime minister was speaking to the BBC’s political editor Laura Kuenssberg, after meeting Mr Biden in Carbis Bay, Cornwall, on Thursday ahead of the G7 summit.
The summit will see the leaders of Canada, France, Germany, Italy, Japan, the US and UK gathering in person for the first time since the pandemic.