The Foreign Office confirmed on Tuesday afternoon that Sir Ivan would be leaving the key Brussels post after it was first reported by The Financial Times.
Sir Ivan was recently attacked by Brexit campaigners for “gloomy pessimism” after he reportedly warned Theresa May it could take ten years to negotiate the UK’s exit from the EU.
But others warned the loss of such an experienced diplomat would hurt the UK’s negotiations.
Sir Ivan had been planning to leave his post in November.
A government spokesman 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.”
Hilary Benn, the Labour chairman of the Commons Brexit committee, said the departure of the diplomat came at a bad time given the UK was about the begin the “most important negotiation the country has engaged in for decades”.
“There could not be a more crucial time for the British person in Brussels,” he told the BBC. “It’s an absolutely vital job.”
May has said she intends to trigger Article 50, the formal process of leaving the EU and beginning negotiations with Brussels, by the end of March.
Veteran Tory MP Sir Nicholas Soames said it “really very bad news indeed” as the UK “cannot afford to lose people of this calibre and experience”.
Former deputy prime minister Nick Clegg, who is now Lib Dem Brexit spokesman, said the resignation of “somebody as experienced as Sir Ivan Rogers is a body blow to the Government’s Brexit plans”.
“I worked for Ivan Rogers in the EU twenty years ago - then he worked for me and the rest of the Coalition Government several years later,” he said.
“Throughout all that time Ivan was always punctiliously objective and rigorous in all he did and all the advice he provided. If the reports are true that he has been hounded out by hostile Brexiteers in Government, it counts as a spectacular own goal.
“The Government needs all the help it can get from good civil servants to deliver a workable Brexit.”
And Nick MacPherson, the former top civil servant at the Treasury, said it was a “huge loss” and criticised the apparent “willful & total destruction of EU expertise” in the government.
But Sir Ivan’s resignation was welcomed by Brexit campaigners including Nigel Farage.
Ukip’s deputy chair Suzanne Evans responded to the news by tweeting: “excellent. An opening for a dedicated Brexiteer!”
And Gerard Batten MEP, UKIP’s Brexit spokesman, suggested Farage should be given the job.
“Perhaps Nigel Farage would consider taking up the post? After all he ably demonstrated in the Referendum campaign that he knows more about the EU than any other British politician, and he can be relied upon to defend Britain’s interests,” he said.
In December, Tory MP and lead Brexit campaigner Dominic Raab, attacked Sir Ivan for being too pro-EU after he said negotiations could take until the mid-2020s. “Let’s not be consumed by Sir Ivan’s gloomy pessimism, let’s get behind the Government, let’s set out the case for a strong, post-Brexit relationship with the EU on trade, security, and other areas,” Raab said.
Author: Ned Simons