Sir Keir Starmer offered his congratulations to Donald Trump as the Republican was sworn in as the 47th president of the United States on Monday, 20 January.
The British prime minister vowed that the special relationship between the UK and the US will "continue to flourish for years to come" as the leaders "deliver for people on both sides of the Atlantic."
As Mr Trump took the oath of office at the US Capitol's Rotunda, he swore to "preserve, protect and defend" the US.
