British Prime Minister Theresa May's uneasy Brexit truce was shattered Thursday as Indian-origin Shailesh Vara became the first of the four ministers to resign over a "half-way house" divorce deal with the European Union. Minutes after Vara stepped down as Northern Ireland minister, Prime Minister May was hit by a bigger blow as her Brexit Secretary Dominic Raab resigned from the Cabinet saying he "cannot in good conscience" support the draft of the\u00a0 withdrawal agreement with the 28-member bloc. "We are a proud nation and it is a sad day when we are reduced to obeying rules made by other countries who have shown that they do not have our best interests at heart. We can and must do better than this. The people of the UK deserve better," said Vara, Conservative Party MP for North-West Cambridgeshire, who has been a minister in the Northern Ireland Office (NIO) since January. He attacked the draft withdrawal agreement which would form the basis of the UK's exit from the EU by March 2019 as a "half-way house with no time limit on when we will finally become a sovereign nation". Raab, who took charge as Secretary of State for Exiting the EU after his predecessor David Davis stepped down in protest over May's Brexit negotiations in July, said the proposed arrangement to avoid a post-Brexit border with Northern Ireland is a "very real threat to the integrity of the United Kingdom". "I cannot support an indefinite backstop arrangement where the EU holds a veto over our ability to exit. 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 exit the arrangement," he said. Raab's resignation was followed by another pro-Brexit minister, work and pensions secretary Esther McVey, announcing that she is resigning from the Cabinet over the issue. Another junior Brexit minister Suella Braverman quit over Brexit, shortly after her former boss Raab quit office. "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," Braverman said in a tweet. The resignations are being seen as a sign of bigger troubles ahead for May, who is set to defend the agreement before MPs in the House of Commons on Thursday. "I firmly believe that the draft Withdrawal Agreement was the best that could be negotiated, and it was for the Cabinet to decide whether to move on in the talks," she said in her statement at the Downing Street doorstep after hours of talks with her top team on Wednesday evening. "The choices before us were difficult, particularly in relation to the Northern Ireland backstop. But the collective decision of Cabinet was that the Government should agree the draft Withdrawal Agreement and the Outline Political Declaration \u2013 this is a decisive step which enables us to move on and finalise the deal in the days ahead," she said. There were already rumblings that while she claimed the Cabinet had collectively given its backing to her deal, many ministers had spoken out against it and were not entirely happy with the final text. The biggest sticking point remains over what is termed as a Northern Ireland backstop, which leaves the EU with the option of keeping the whole of the UK within a common Customs Union if a future trading relationship fails to be thrashed out during the 21-month transition period, set to run until December 2021. The resignation of Raab, the man involved with the actual drafting of the agreement with EU counterparts, throws Prime Minister May's leadership in turmoil. "Raab's resignation marks the end of the PM's Withdrawal Agreement. This is very serious; the PM will clearly be considering her position. My own view is that we need a government of national unity and we need it now," Remain-backing Conservative MP Anna Soubry tweeted. The markets also reacted sharply, with the Pound falling heavily against most major currencies after Raab's decision to resign. Meanwhile, European Council president Donald Tusk confirmed November 25 as the date of an emergency summit where the remaining 27 EU member states are set to formally approve the withdrawal agreement. Northern Ireland's Democratic Unionist Party (DUP), which props up the minority Tory government, have also been vocal in their criticism, threatening to break their deal with the Conservatives and vote down the deal. DUP Brexit spokesperson Sammy Wilson led praise for Vara, who he described as "a man of his word" for taking the stand to step down as Northern Ireland minister. Vara was among the few Indian-origin junior ministers in the government, alongside fellow Leave supporters Rishi Sunak, who is a parliamentary under-secretary in the housing department, and Suella Fernandes Braveman, who is an under-secretary in the Department for Exiting the EU. Remain-supporting Alok Sharma is minister of state for employment. The fresh turmoil comes as Britain continues to try and thrash out the basis of its exit from the EU, after a referendum over its membership of the economic bloc resulted in a 52 per cent vote in favour of Brexit in 2016. As the chaos within government circles gathers momentum, calls for a second "people's vote" over the issue of Brexit is also gaining ground.