Sir Ivan Rogers has quit just months before Theresa May triggers formal Brexit negotiations with the EU in which he would have been expected to play a major role. 

He was expected to be in post until October 2017 but will instead leave within the coming weeks and a replacement will be announced in due course.

A UK Government spokesperson said: "Sir Ivan Rogers has resigned a few months early as UK Permanent Representative to the European Union. 

"Sir Ivan has taken this decision now to enable a successor to be appointed before the UK invokes Article 50 by the end of March. We are grateful for his work and commitment over the last three years".

The Financial Times reported that Sir Ivan did not explain the reasons behind his decision when he informed staff of his decision to leave early, but that he played down his resignation by stating it was only slightly ahead of his planned departure date.

The news has prompted concerns that the UK will get a worse Brexit deal than it would have if he remained part of the team.

Charles Grant, director of the Centre for European Reform think-tank, said: "Ivan Rogers's resignation makes a good deal on Brexit less likely. One of the very few people at the top of British government who understands [the] EU".

David Fuller's view

Sir Ivan may understand the EU’s intentionally convoluted procedures but he was one of Cameron’s appointees to this insiders’ club and they had different plans.  He should have resigned with Cameron and I think Prime Minister May’s team ought to appoint their own pro-Brexit representatives for negotiating with the EU. 

These need not be mainly civil servants.  I would prefer to see some smart, tough and pro-Brexit businessmen and lawyers among the UK’s negotiating team.   Additionally, the UK should push for an early exit from the EU, as I have said repeatedly.  There is little to be gained from lengthy negotiations.  These would only be divisive and frustrating in terms of UK business planning.  A lengthy exit would also delay the establishment of new trade links with other countries.  EU governments will be under pressure from their own corporations, to negotiate mutually sensible trade terms with the UK, once we have left this closed shop. 

Here is a PDF of The Telegraph’s article.