| Downing Street said Sir Tim would "bring his trademark energy and creativity" to the job |
Senior diplomat Sir Tim Barrow has been appointed the UK's new ambassador to the EU, replacing Sir Ivan Rogers.
Sir Ivan, whose exit came earlier than planned, sparked a row after his resignation note criticised "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, who was the UK's ambassador in Moscow from 2011 to 2015, has also advised a succession of foreign secretaries as well as holding other roles in the UK's EU mission.
'Wider strains in Whitehall'
John Pienaar, BBC deputy political editorThe resignation of Sir Ivan Rogers has revealed more than the difficulty and complexity of Britain's EU divorce.
It has highlighted wider strains in Whitehall between some mandarins and some ministers, up to and including Theresa May.
Mandarins and ambassadors perennially advise more junior mandarins on the importance of speaking truth to power.
On this occasion, Sir Ivan's leaked farewell memo can fairly be read as a protest and a warning. Concern is growing among some high-ranking officials that ministers don't understand or won't admit the scale of the task they're facing.
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Sir Tim 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 welcomed the appointment and Tom Fletcher, a former UK ambassador to Lebanon, told BBC Radio 4's Today programme: "It's the toughest negotiation in our lifetimes and I think he is up to it. I have seen him in Brussels.
He knows the corridors, he knows the characters. "But actually more importantly I saw him in Moscow where he was incredibly resilient as ambassador there, dealing with (Vladimir) Putin in a very testing time in our relationship and Tim had a reputation of being bulletproof out there."
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."
'Disagreeable messages'
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."
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