The UK has appointed its current envoy to the United Nations Karen Pierce as its new ambassador to the United States, making her the first woman to hold the post. Ms Pierce, a career diplomat, will replace Kim Darroch whose position had been left empty since his July 2019 resignation over leaked diplomatic cables which embarrassed the White House. The cables showed Mr Darroch had written back to London calling US President Donald Trump “clumsy and inept” and dismissing his administration as “uniquely dysfunctional”. In an unprecedented escalation, Mr Trump responded to the leaks calling Mr Darroch a “very stupid guy” and “pompous”, exerting pressure on the British government to sack the ambassador. Because of the acrimonious resignation of the previous British ambassador and the delicate junction in US-UK relations, Mr Darroch’s replacement had been keenly anticipated. Ms Pierce previously served in Washington as private secretary to the British ambassador between 1992 and 1996. She has worked as the United Kingdom’s permanent representative to the UN since March 2018. Prior to that role, Ms Pierce served as the director general for political affairs at the Foreign and Commonwealth Office (FCO) in London. In a statement, the FCO said the request for Ms Pierce’s appointment has been sent to the US government for its agreement. “It is a time of huge opportunity for the friendship between the UK and US and I am delighted that Karen Pierce will take forward this exciting new chapter in our relationship,” Foreign Secretary Dominic Raab said. “We’re proud to be sending to Washington such an outstanding diplomat, and I warmly congratulate her on her appointment,” he added. Ms Pierce said she was honoured to be chosen as the UK’s Washington envoy. “There is a deep bond between Britain and the US, built on many pillars,” she said. “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,” the new ambassador added. In response to her appointment, the FCO’s permanent under-secretary Sir Simon McDonald tweeted an image of a mirror, writing that it would have to be flipped. The British foreign office had installed 13 mirrors to represent ambassadorial posts, half of those in the service, not yet held by women. Britain and the US have been at loggerheads over a number of diplomatic issues in recent months including the possible extradition of the wife of a diplomat wanted for questioning over a fatal car crash and the Iran nuclear deal. However, the most serious clash between the two close allies has been over Britain's decision to allow Chinese firm Huawei limited access to run Britain's new 5G network, against Mr Trump's wishes. The US president was reported by the<em> Financial Times</em> to be "apoplectic" during a recent phone call with UK Prime Minister Boris Johnson. Before he became prime minister, Mr Johnson was criticised for appearing not to back Mr Darroch in his spat with the US president. There had been conjecture that former Brexit Party leader Nigel Farage, a friend of Mr Trump, might be given the post.