The UK Government minister in charge of Brexit has resigned over the terms of the deal to leave the EU.

Dominic Raab says he cannot support the deal in "good conscience" and explained his decision to Prime Minister Theresa May in a letter.

His surprise departure on Thursday came amid a furious backlash from Brexit-backing Tories to the deal agreed by UK and EU negotiators four months ahead of the UK's scheduled withdrawal on March 29.

Esther McVey has also quit her role as work and pensions secretary over May's Brexit plan.

In the Commons, SNP Westminster leader described the deal as "dead in the water".

He complained that Scotland was "not once mentioned in the document" - something he said was "absolutely shocking".

Blackford said: "One hundred mentions of Northern Ireland, mentions of Gibraltar, of Cyprus, of the Isle of Man, but no reference to Scotland.

"Utter contempt has once again been shown to the Scottish Government, its parliament and its people."

May later acknowledged the mechanism for withdrawing from the Irish border backstop "does require mutual consent, it is for both sides to agree that".

Other resignations included Suella Braverman and aide to education minister Anne-Marie Trevelyan both resigned.

Hours earlier Shailesh Vara had quit as minister of state for Northern Ireland, saying Mrs May's agreement, "leaves the UK in a halfway house with no time limit on when we will finally be a sovereign nation".

Raab posted the resignation letter on to his Twitter account on Thursday explaining his decision.

He said: "It has been an honour to serve in your government as justice Minister, housing minister and Brexit secretary.

"I regret to say that, following the Cabinet meeting yesterday on the Brexit deal, I must resign.

"I understand why you have chosen to pursue the deal with the EU on the terms proposed, and I respect the different views held in good faith by our colleagues."

"For my part, I cannot support the proposed deal for two reasons. First I believe that the regulatory regime proposed for Northern Ireland presents a very real threat to the integrity of the United Kingdom.

Second, I cannot support an indefinite backstop arrangement, where the EU holds a veto over our ability to exit. The terms of the backstop amount to a hybrid of the EU Customs Union and Single Market obligations.

"No democratic nation has ever signed up to be bound by such an extensive regime, imposed externally without any democratic control over the laws to be applied, nor the ability to decide to exit the arrangement.

"That arrangement is now also taken as the starting point for negotiating the Future Economic Partnership. If we accept that, it will severely prejudice the second phase of negotiations against the UK.

"Above all, I cannot reconcile the terms of the proposed deal with the promises we made to the country in our manifesto at the last election. This is, at its heart, a matter of public trust.

"I appreciate that you disagree with my judgment on these issues. I have weighed very carefully the alternative courses of action which the government could take, on which I have previously advised.

"Ultimately, you deserve a Brexit Secretary who can make the case for the deal you are pursuing with conviction. I am only sorry, in good conscience, that I cannot.

"My respect for you and the fortitude you have shown in difficult times, remains undimmed."

The Esher and Walton MP only lasted four months as Brexit secretary after taking over from David Davis in July.

A short time later McVey posted a copy of her resignation letter on Twitter and wrote: "Earlier this morning I informed the Prime Minister I was resigning from her Cabinet."

Scotland's First Minister Nicola Sturgeon tweeted following the announcement and said: "I just hope that Esther McVey takes the travesty that is Universal Credit out the door with her."

Braverman wrote on Twitter: "It is with deep regret and after reflection that I have had to tender my resignation today as a Brexit Minister.

"Thank you for the opportunity. I look forward to working to support Brexit from the Backbenches.

"This has not been an easy decision."

Trevelyan added: "It is with sadness that I have submitted my letter of resignation as PPS to the Education Ministers to the Prime Minister.

"It has been a joy and a privilege to have served in defence and education."

Vara wrote: "With much sadness and regret I have submitted my letter of resignation as a Northern Ireland Minister to the Prime Minister. A copy of my letter is attached.

"It has been a joy and privilege to serve in the Northern Ireland Office and I will always cherish the fondest memories."

Shadow Cabinet Office minister Jon Trickett said: "The government is falling apart before our eyes as for a second time the Brexit Secretary has refused to back the Prime Minister's Brexit plan.

"This so-called deal has unravelled before our eyes.

"This is the 20th minister to resign from Theresa May's government in her two-year premiership.

"Theresa May has no authority left and is clearly incapable of delivering a Brexit deal that commands even the support of her Cabinet - let alone Parliament and the people of our country."

The resignations came as European Council president Donald Tusk announced an extraordinary meeting of EU leaders in Brussels on November 25, at which the withdrawal agreement and a political declaration on future relations will be finalised and formalised.

Westminster is braced for further resignations, amid widespread expectations that the Prime Minister may face a challenge to her position from Conservative MPs submitting letters of no confidence in her leadership.