The UK's chief Brexit negotiator just quit without warning

The man who was set to lead the U.K.’s complicated negotiation process with the European Union on how it will exit the alliance has unexpectedly quit, leaving a major knowledge gap in the country’s diplomatic ranks ahead of the crucial talks.

Sir Ivan Rogers, one of the the U.K.’s most experienced diplomats, resigned on Tuesday, 10 months ahead of schedule and just three months before the government plans to trigger Article 50 and begin the process of leaving the EU.

The government said Rogers took the decision to leave now so that a successor could be appointed before the U.K. invokes Article 50, but others see his decision to leave as an indication that officials in Brussels are becoming increasingly frustrated at the government’s unwillingness to listen to their advice.

“I would not expect him to comment further but everyone knows that civil servants are being increasingly inhibited in offering objective opinion and advice to ministers,” Lord Mandelson, the former Labour business secretary and former European trade commissioner, said.

Seen as a Europhile and a pessimist when it came to Brexit, Rogers conducted David Cameron’s renegotiation with the EU before the referendum last June. However in December he told the government that negotiations for a Brexit could take as long as a decade, though the government subsequently said the diplomat was simply reporting the thoughts of other EU leaders.

Nick Clegg, a former deputy prime minister, suggested Rogers’ departure was the result of pressure from certain MPs. “If the reports are true that he has been hounded out by hostile Brexiteers in government, it counts as a spectacular own goal,” Clegg told the Guardian. “The government needs all the help it can get from good civil servants to deliver a workable Brexit.”

Nicholas Macpherson, the former permanent secretary of the Treasury, has accused the government of allowing a vacuum of expertise to be created within Whitehall. Macpherson said Rogers was a “huge loss” and he couldn’t understand the “wilful and total destruction of EU expertise” in the civil service.

As Macpherson alluded to in a tweet, Rogers is not the first top EU diplomat to leave the government ranks in recent years. His predecessor Jon Cunliffe is now deputy governor of the Bank of England, while Michael Ellam left his position dealing with EU policy at the Treasury for a job at HSBC. Tom Scholar, who was the prime minister’s Europe adviser became head of the Treasury last year.

Some have welcomed the move. UKIP’s Brexit spokesman Gerard Batten said the party’s former leader Nigel Farage should replace Rogers. Responding to the call, Farage told the Press Association that “it would be lots of fun, but it’s never going to happen.”

Farage added that more diplomats should consider resigning: “I think it would be appropriate if a lot more people in that position, British ambassadors, left. The world has changed. The political establishment in this country and the diplomatic service just doesn’t accept the vote.”

British Prime Minister Theresa May’s plans to trigger Article 50 in March could be delayed significantly if the Supreme Court upholds a High Court decision which says she would need the approval of parliament before going ahead with the process. A decision is expected later this month.