Senior diplomat Sir Tim Barrow has been appointed the UK’s new ambassador to the EU, replacing Sir Ivan Rogers.
Downing Street described the former ambassador to Moscow, who will now play a key role in the UK’s Brexit talks, as a “seasoned and tough negotiator”.
Sir Ivan’s exit, which came earlier than planned, sparked a row with his resignation note criticising “muddled thinking” from ministers.
Some MPs had accused him of being “half-hearted” towards Brexit.
Critics of the outgoing ambassador were accused of trying to “politicise” the civil service, with a trade union saying there was a “deafening silence” from ministers in defending officials’ independence.
Sir Tim was the UK’s ambassador to Moscow from 2011 to 2015. He has also advised a succession of foreign secretaries as well as holding other roles in the UK’s EU mission.
He said he was “honoured” to be appointed to the role, officially called the UK’s permanent representative to the EU, adding that he would ensure “the right outcome” for the UK after Brexit.
Downing Street said Sir Tim had “extensive experience of securing UK objectives in Brussels” and would “bring his trademark energy and creativity to this job”.
Foreign Secretary Boris Johnson and Brexit Secretary David Davis both issued statements welcoming the appointment.
But former UKIP leader Nigel Farage was less enthusiastic, tweeting: “Good to see that the government have replaced a knighted career diplomat with…. a knighted career diplomat.”
BBC diplomatic correspondent James Landale said Sir Tim’s record was less likely to be criticised by Brexit supporters than that of some other potential candidates, adding: “It would be very hard to say that Sir Tim Barrow is an out and out pro-European.”
In his farewell note to fellow UK diplomats in Brussels, Sir Ivan said: “I hope you will continue to challenge ill-founded arguments and muddled thinking and that you will never be afraid to speak the truth to those in power.
“I hope that you will support each other in those difficult moments where you have to deliver messages that are disagreeable to those who need to hear them.”
On the UK’s Brexit negotiations with the EU, he said he did not yet know the government’s negotiating plans for Brexit, telling colleagues “serious multilateral negotiating experience is in short supply in Whitehall”, adding this was not the case in the European Commission or in the European Council.
He said the government would only succeed if it “negotiates resolutely”, adding, in a reference to the remaining 27 EU states: “Senior ministers, who will decide on our positions, issue by issue, also need from you detailed, unvarnished – even where this is uncomfortable – and nuanced understanding of the views, interests and incentives of the other 27.”
Sir Ivan had previously warned ministers that EU-UK trade talks could take a decade to complete, advice revealed by the BBC last month.
Politicians on both sides of the EU debate were divided in their response to Sir Ivan’s resignation, with pro-EU MPs saying the loss of his experience at a crucial time was a blow to the government’s negotiating strategy.
Labour has demanded a statement from Brexit Secretary David Davis.
But former cabinet minister Iain Duncan Smith, who backed Brexit, was among those criticising the outgoing diplomat, saying when a civil servant “starts going public”, ministers “can no longer trust that individual”.
Another pro-Brexit Conservative, Sir Peter Lilley, said half of Sir Ivan’s parting note to his fellow UK diplomats in Brussels read “like a CV” and the other half “like some degree of sour grapes”.
These attacks were condemned by former Foreign Office permanent secretary Lord Ricketts, who said he was “really concerned at the undertone of denigration” of Sir Ivan and said it was vital for ministers to “stand behind” his successor.
Dave Penman, leader of the FDA union for senior Whitehall staff, said he had “a lot of concern” about some of the comments, adding: “What surprises me is the deafening silence from ministers who should be taking to the airwaves to defend the integrity and capability of the impartial civil service.”