Allies of Boris Johnson insist that if, as expected, he becomes the next British prime minister, he will be the one to appoint the new ambassador to Washington following the resignation of Sir Kim Darroch.

The ambassador stepped down after a leak of diplomatic cables in which he painted an unflattering portrait of President Trump and his “inept” and “chaotic” administration.

The leak has been widely considered in Britain as a move by pro-Johnson supporters of Brexit (Britain's departure from the European Union) to oust an opponent of Brexit, as Darroch, a former ambassador to Brussels, was viewed.

Darroch's replacement will have a key role in rebuilding the "special relationship," a term coined by Winston Churchill, between the two countries as Britain tries to find its new place in the world after Brexit.

Johnson is in the final two of the Conservative Party leadership contest and almost certain to be elected by party members, among whom he enjoys overwhelming support over Jeremy Hunt, the foreign secretary, who oversees Britain's ambassadors.

The last 10 British ambassadors to Washington, covering 40 years, have been career diplomats and Knights of the Realm.

Peter Jay, who was ambassador from 1977 to 1979, was a journalist and the son-in-law of British Prime Minister James Callaghan when he was appointed at age 40. Given the idiosyncratic nature of Trump and the manner of Darroch's departure, Johnson may well be tempted to select a non-diplomat who is a public supporter of Brexit.

Downing Street has not commented on whether Theresa May will nominate a candidate before she is expected to stand down on July 24, but senior diplomats say she is in too weak a position to force through an appointment. Even if she were to name a new ambassador, the nominee might not accept because of the danger that they might be undermined by Johnson as soon as he takes over.

Liz Truss, Treasury chief secretary, was the latest ally of Johnson (the overwhelming favorite to win the Conservative Party ballot for party leader) to insist he would be responsible for naming a replacement.

She said on Thursday that the civil servant who heads the Foreign Office had already signaled the recruitment process would likely take months. "The permanent secretary of the Foreign Office has been clear that this is a job that is going to take months rather weeks to recruit for, so I think the question is academic," she told a lunch event in Westminster.

"It's likely that the new ambassador will be selected and appointed by the new prime minister."

Foreign Office insiders believe Darroch was targeted in part because he was not seen as sufficiently pro-Brexit. But they say the real target may have been Sir Mark Sedwill, the head of the British civil service, who has warned that Brexit could spark a recession but who was in the running to take over from Darroch when he was due to retire at the end of the year.

“Who knows who leaked this but it throws the orderly succession off track and the timing makes it impossible for May to appoint someone,” said a British diplomat.

Brexiteers argue that Johnson must be allowed to appoint a like-minded ambassador, one who will allow Britain to secure a trade deal with America. Rather than seeing the U.K. as a bridge to Europe, they want American leaders to see Britain as an essential ally in its own right.

Ross Thomson, a member of Parliament for Aberdeen who is running Johnson’s campaign in Scotland, said working closely with the U.S. was at the heart of how the likely next prime minister would steer foreign policy.

“I know that he is an Atlanticist; he really does value the special relationship and feels post-Brexit that he needs to make working with the U.S. a priority — not just in terms of trade, but in security and research as well,” he said.

Johnson allies briefed British newspapers that he must be allowed to make the appointment. Julian Lewis, the Conservative chairman of the defense select committee, has warned against the “temptation for an outgoing prime minister to appoint to a plum job one of her inner circle."