Boris Johnson has refused to say he would keep Sir Kim Darroch as Britain’s ambassador to the US if he became prime minister.During a live television debate between the two Tory candidates to become the next prime minister, the former foreign secretary initially evaded the question and refused to commit himself on Sir Kim’s fate, but when pressed said he wouldn’t be “presumptuous”.Jeremy Hunt, by contrast, said he would keep Sir Kim in place until he retires at the end of the year.“Who chooses our ambassadors is a matter for the United Kingdom government and the United Kingdom prime minister so I’ve made clear that if I am our next prime minister, the ambassador in Washington stays,” Mr Hunt said.Mr Johnson tried to put the focus on his rival by questioning whether he would keep the ambassador on beyond Sir Kim’s planned retirement date.He condemned the person who leaked the memos from Sir Kim, and conceded Donald Trump’s criticism of Sir Kim was “not necessarily the right thing to do”.“I’m not going to be so presumptuous as to – what I will say is that I and I alone takes important and politically sensitive jobs,” Mr Johnson said.Donald Trump has insisted he will no longer deal with the UK ambassador after leaked diplomatic cables revealed him calling the US administration “dysfunctional” and “inept”.In one scathing assessment, Sir Kim wrote: “We don’t really believe this administration is going to become substantially more normal; less dysfunctional; less unpredictable; less faction riven; less diplomatically clumsy and inept.”The Foreign Office is investigating who is behind the leak.The US president said Sir Kim was “not liked or well thought of” within the US.There have been suspicions Mr Johnson was interested in making Nigel Farage, who has called for Sir Kim’s sacking, the UK’s ambassador.When asked on BBC Radio 4 whether he would take the job, the Brexit Party leader said: “I don’t think I am the right man for that job.”