Chief Negotiator Olly Robbins will resign from his role in Brexit this summer.
PA understands that the man who has run the Brexit Theresa May agreement may withdraw immediately after the new prime minister takes over his position at the end of July.
Mr. Robbins made a brief takeover before moving on, with reports that he could be employed in the city.
Mr Robbins' departure is the last in the wave of top civil servants dealing with Brexit who announced resignation instead of taking the challenge of delivering Brexit within 100 days under a new leader.
Tom Shinner, Director of Policy Coordination and Delegation at the Departure of the EU, and Karen Wheeler, General Director of the Group for Delivery and Certification of Her Majesty's Majesty, both announced that she would give up.
Leadership candidate Tory Jeremy Hunt interviewed the report on the complaint in Manchester and said that "a good time to change our approach" to the members of Tori.
Mr. Hunt said, "I did not agree with the approach we have taken in many areas of the Brexit negotiations.
"I was a loyal minister – I think it is very important that the prime minister has a faithful foreign minister – but I was not a believer in the security mechanism and I did not believe he would go through parliament, so I think this is a good time to change our approach.
"I will not say something about a civil servant I know is incredibly difficult, though there are issues I disagree with.
"But I think it is time to do this, to make a different arrangement and the one that can be obtained through parliament."
It is expected that both candidates will soon disclose the new negotiating teams of Brexit, and Mr Hunt will recruit two Canadians with the aim of securing free trade arrangements in the style of Chandiani and Mr Johnsons in the Brexiteers including Jacob Rees-Mogg.