The prime minister will meet his American counterpart after publicly refusing to back his move to send the weapons – which are banned by 123 countries – to Kyiv.
US President Joe Biden will fly into the UK on Sunday amid tensions over his decision to send cluster bombs to Ukraine.
Air Force One is expected to touch down at Stansted Airport this evening before Mr Biden meets with both Rishi Sunak in Downing Street and the King at Windsor Castle on Monday.
Mr Biden’s stopover in Britain comes ahead of a crunch two-day NATO summit in Vilnius, Lithuania, on Tuesday, in which leaders are set to discuss the war in Ukraine and the future of the military alliance as several nations clamber to join.
But it comes as controversy grows over the White House’s announcement that it will send cluster munitions to Kyiv, despite use of the bombs being banned by 123 nations across the world – including Britain.
Mr Biden, who will be accompanied on his European tour by his Secretary of State Antony Blinken, called it a “difficult decision”, but claimed he had to act because “the Ukrainians are running out of ammunition”.
However, Mr Sunak publicly refused to back the move while speaking to reporters on Saturday, and pointed out that the UK is a “signatory to a convention which prohibits the production or use of cluster munitions and discourages their use”.
