The government has named Dame Karen Pierce as the new ambassador to the US.
Dame Karen – who is currently the UK’s permanent representative to the United Nations – will become the first woman in the post.
She replaces Sir Kim Darroch, who resigned in 2019 after he called President Donald Trump’s administration “clumsy and inept” in leaked emails.
Dame Karen said she hoped to “strengthen the special relationship” between the countries.
Prime Minister Boris Johnson called her “an outstanding and accomplished diplomat”, tweeting: “I can think of no better person to drive forward our hugely important relationship with the United States at this time.”
Foreign Secretary Dominic Raab also congratulated Ms Pierce on her appointment, saying it was “a time of huge opportunity for the friendship between the UK and US”.
The posting comes ahead of post-Brexit trade deal negotiations with the US, and amid rows between the two nations over the future of the Iran nuclear deal and the use of Huawei technology.
Dame Karen joined the Foreign and Commonwealth Office (FCO) in 1981.
She held posts in countries around the world, including Japan, Switzerland and the US, before becoming the British Ambassador in Afghanistan between 2015 and 2016.
She then returned to London as the FCO’s chief operation officer until her posting at the UN.
After the announcement of her new role, Dame Karen said: “I am honoured to have been asked to represent the UK in the US. I think it is the UK’s single most important relationship. There is a deep bond between Britain and the US, built on many pillars.
“We have a fantastic cross-government team across the US and I look forward to working with them to strengthen and even further deepen the special relationship between our two countries and peoples.”
Mr Raab added: “I am delighted that Karen Pierce will take forward this exciting new chapter in our relationship.
“We’re proud to be sending to Washington such an outstanding diplomat, and I warmly congratulate her on her appointment.”
