Dominic Raab has been appointed to replace David Davis after the Brexit secretary had a major row with Theresa May over her plans for post-Brexit relations with the EU.
Mr Davis said he was “very clear” on Friday that he did not back Ms May's Brexit plan and said he told her he would be the “odd man out” on it.
His resignation as Brexit secretary deals a heavy blow to the stability of the prime minister’s administration, with two other junior ministers almost immediately following suit.
He is the sixth senior cabinet minister to leave the government since November and comes as Ms May prepares to make a statement to the Commons and address her backbenchers this evening at the 1922 committee of Conservative MPs.
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Asked if it was a problem, he replied: "Not for us. We are here to work."

Bookies slash odds on a general election being called after David Davis resignation
But Mrs May remains favourite to be leading country into the new yearHe told reporters the EU would "continue to negotiate in good faith" with the prime minister following the resignation of Mr Davis.

How David Davis's resignation will go down in Brussels
David Davis has been side-lined in talks for months
Dominic Raab replaces David Davis as Brexit Secretary
Dominic Raab has replaced David Davis as the Brexit secretary after the cabinet minister dramatically resigned from his government post. In less than nine months before Britain is expected to leave the bloc, the prime minister was forced to appoint the current housing minister to the critical position. Mr Davis’ resignation is a major blow to Ms May’s already fragile government and has led to speculation that she could face a challenge to her leadership if enough of backbench MPs submit letters of no confidence.Sir Graham told the Press Association: "My view ever since I became chairman of the '22 is that it would be entirely improper ever to comment in any way on that subject, because inevitably a commentary could influence the course of events."
"No comment will be made by the '22 unless and until the 48 letters required to trigger a vote are received," he said.

David Davis accuses Theresa May of 'giving away too much, too easily' in Brexit talks
Ex-Brexit secretary says prime minister is falsely 'painting' her Chequers agreement as 'returning control, to the House of Commons'"I think what the prime minister needs to do is give up on the Chequers proposals which, David Davis has pointed out in his resignation letter, don't actually deliver Brexit."
He says he will "congratulate" Davis for resigning and shows what the PM is offering "isn't really
He says he has not personally sent a letter of no confidence in the PM to the 1922 Committee.

David Davis' resignation letter claims UK left in 'weak' Brexit negotiating position
Theresa May's reply says she 'disagrees' with departing minister's view of Chequers talks
Theresa May faces leadership challenge threat from Tory Brexiteers
MPs tell The Independent they believe there could be enough MPs to trigger contest"That is not weakening, that is actually enhancing the effectiveness of the strategy."
He said he wanted to speak to Ms May "face to face" on Sunday night but had spoken to her by telephone as she was at her home in Sonning, Berkshire.
He added: "I like Theresa May, I think she is a good PM. We have a difference over this strategy."
He said other cabinet members had asked for changes to be made to the Brexit policy on Friday, but none had been made.
He admitted he had "lost the argument in cabinet", adding: "In my view, this policy has got a number of weaknesses.
"I would be front and centre in delivering this policy, explaining it to the House, persuading the House it is right, and then going out and delivering it with the EU.
"Frankly, just as it was known what the policy was, it was also known I had concerns about it.
"It would not have been a plausible thing to do and I wouldn't have done a good job at it."
David Davis' resignation letter in full
Dear Prime Minister,
As you know there have been a significant number of occasions in the last year or so on which I have disagreed with the Number 10 policy line, ranging from accepting the Commission’s sequencing of negotiations through to the language on Northern Ireland in the December Joint Report.
At each stage I have accepted collective responsibility because it is part of my task to find workable compromises, and because I considered it was still possible to deliver on the mandate of the referendum, and on our manifesto commitment to leave the Customs Union and the Single Market.
I am afraid that I think the current trend of policy and tactics is making that look less and less likely. Whether it is the progressive dilution of what I thought was a firm Chequers agreement in February on right to diverge, or the unnecessary delays of the start of the White Paper, or the presentation of a backstop proposal that omitted the strict conditions that I requested and believed that we had agreed, the general direction of policy will leave us in at best a weak negotiating position, and possibly an inescapable one.
The Cabinet decision on Friday crystallised this problem. In my view the inevitable consequence of the proposed policies will be to make the supposed control by Parliament illusory rather than real. As I said at Cabinet, the “common rule book” policy hands control of large swathes of our economy to the EU and is certainly not returning control of our laws in any real sense.
I am also unpersuaded that our negotiating approach will not just lead to further demands for concessions. Of course this is a complex area of judgement and it is possible that you are right and I am wrong. However, even in that event it seems to me that the national interest requires a Secretary of State in my Department that is an enthusiastic believer in your approach, and not merely a reluctant conscript. While I have been grateful to you for the opportunity to serve, it is with great regret that I tender my resignation from the Cabinet with immediate effect.
Yours ever, David Davis

How David Davis's resignation will go down in Brussels
David Davis has been side-lined in talks for months