British Prime Minister Boris Johnson has spoken to Joe Biden for the first time since the new US president was inaugurated.
Mr Johnson said on Twitter that he looked forward to "deepening the longstanding alliance" between the UK and the US as they drove a "green and sustainable recovery from Covid-19".
A Downing Street
spokesman said Mr Johnson warmly welcomed the president's decision to rejoin the Paris Agreement on climate change and the World Health Organization - both abandoned by Mr Biden's predecessor, Donald Trump.
Mr Biden was sworn in as president and Kamala Harris as vice-president in a ceremony in Washington on Wednesday.