(Bloomberg) -- Foreign Secretary Jeremy Hunt told U.K. diplomats to speak “truth to power” as he sought to rally morale after a transatlantic row over leaked diplomatic memos led to Britain’s U.S. envoy quitting his post.

Kim Darroch quit as ambassador to Washington after memos were leaked in which he criticized Donald Trump and his administration. His resignation followed a barrage of insults from the U.S. president on Twitter and the failure of former Foreign Secretary Boris Johnson -- the favorite to succeed Theresa May as prime minister -- to back him in a televised debate Tuesday.

“Please keep speaking up without fear or favor,” said Hunt, who’s vying with Johnson for the top job. “You will always get all the support you need to carry out your vital work,” he said in a message to diplomats released to reporters by his campaign team.

Hunt’s remarks seek to capitalize on Johnson’s failure to back Darroch, which has been characterized in U.K. newspapers as a misstep by the front-runner in the leadership contest. Hunt himself described comments made by Trump about both Darroch and May as “disrespectful and wrong.” He said the U.K. government alone will determine its diplomatic appointments.

May’s office has said Darroch’s replacement will be named “in due course,” but Johnson’s supporters say it’s not a decision May should make. Chief Secretary to the Treasury Liz Truss, one of Johnson’s earliest backers, told reporters Thursday that the appointment is for the next prime minister to make. She was also critical of Trump’s tweets, which were disparaging of May’s Brexit deal as well as insulting Darroch.

“I’m a patriot so I don’t like to hear any foreign leader slagging off our government,” Truss said. “But fundamentally whatever the rights and wrongs of the issue, the deal has failed to get through on numerous occasions. It’s a dead duck. We now need a fresh approach, it’s more urgent than ever before.”

--With assistance from Jessica Shankleman.

To contact the reporter on this story: Alex Morales in London at amorales2@bloomberg.net

To contact the editors responsible for this story: Tim Ross at tross54@bloomberg.net, Robert Jameson

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