Joe Biden has been accused of a “negative” mindset amid a row over Nato ahead of his meeting with Rishi Sunak in Downing Street today.

The US President, who arrived at Stansted last night ahead of talks with the Prime Minister, was seen to have undermined Mr Sunak by insisting on the eve of his visit that Ukraine is not ready for Nato membership.

Robert Courts, the Conservative MP for Witney and a former transport minister: “Biden is technically correct that Ukraine’s immediate entry into Nato is difficult to see - as President Zelensky himself has accepted - partly because of the obvious ongoing war.

“Nato is meant to deter and an immediate entry would embroil members in immediate conflict, and partly because of the inability to address interoperability issues in that time. Nonetheless, it is disappointing to see such a negative statement from the President at a time when we should be offering as much moral as well as material support to Ukraine.”

There is also disagreement between the UK and the US over Washington’s controversial decision to send cluster munitions to Ukraine, as the British government is among signatories to a convention which bans their use.

Sir John Redwood, a former head of the No 10 policy unit under Margaret Thatcher, suggested the point of Mr Biden’s visit was “to try to change the UK’s view on cluster bombs”.