Tim Barrow, a former ambassador to Moscow who has twice served in Brussels, has been tapped to take over from Ivan Rogers, who resigned on Tuesday.

Barrow was Britain's ambassador to Moscow until 2015, and in March 2016 he became political director at the Foreign Office. He has formerly acted as first secretary at UKRep, Britain's mission to the EU.

Announcing his resignation on Tuesday, Rogers sent an email to staff condemning "ill-founded arguments and muddled thinking" over Brexit.

He made it clear he was still in the dark over Prime Minister Theresa May's objectives.

"We do not yet know what the government will set as negotiating objectives for the UK's relationship with the EU after exit," Rogers said in his email, adding that he was quitting nine months early so his successor could see through the whole negotiation process.

Rogers was criticized last month for saying it could take 10 years for Britain to conclude a trade deal with the EU.

"His resignation is not a surprise for those who work with him," one European diplomat told French agency Agence France-Presse.

"He was very competent, but not convinced by the Brexit decision and the British government line, leading the UK into an area of dangerous uncertainty."

Barrow to play a 'crucial role': Davis

The appointment of the new ambassador was welcomed by Britain's Brexit minister, David Davis. He said Barrow's office will play a "crucial role" in negotiations to leave the EU.

"His knowledge of Brussels means he will be able to hit the ground running at a vital time, and steer UKRep throughout the negotiation period," he said.

"I am confident that with his help, the UK will be able to forge a new relationship with the EU that works to the mutual benefit of both sides."

UK Foreign Minister Boris Johnson said Barrow had been "invaluable" and thanked him for his "relentless energy, wise counsel and steadfast commitment."

The move, meanwhile, was attacked by Nigel Farage, a leading anti-EU figure in the Brexit campaign.

"Good to see that the government have replaced a knighted career diplomat with.... a knighted career diplomat," he wrote on Twitter.

jbh/cmk (AFP, Reuters)