President Trump also mocked Sir Keir to his face during a press conference after the two men had a working lunch, asking if the UK could take on the Russians “on your own?”.
Asked if he could see a situation where US forces could be deployed as a backstop, Mr Trump said: "Well, there is a backstop.
Trump also appeared to give his backing to the UK government’s controversial deal on the Chagos islands – just hours after UK foreign secretary David Lammy admitted the agreement would be sunk if the US vetoed it.
Meeting between the Labour prime minister and US president touched on Ukraine, tariffs, trade deals, the Chagos Islands, Nato and a historic state visit invitation from King Charles.
In a press conference after their Oval Office meeting, the president suggested that a US-UK trade deal could be signed “rather quickly” and might mean that tariffs on UK goods into the US would be unnecessary.
