One in five Tory MPs have now publicly declared an intention to back exit from the EU before David Cameron has secured his Brussels reforms, with a flurry of ministers and backbenchers expected to show their hands over the weekend.

Leading Eurosceptics said they believed MPs would start declaring their allegiances within hours of Cameron holding an emergency cabinet meeting to present any agreement he secures from Brussels, possibly as early as Friday.

Most Conservative MPs have held back from revealing their positions during the renegotiations, but the depth of the split in the party is likely to become clear with a rush of announcements shortly after a deal is confirmed.

The fact that more than 65 MPs are openly backing the leave campaign already suggests that the prime minister’s renegotiations have not been a triumph with the rank and file of the party, despite his hopes of keeping most of his cabinet on side. Some estimates suggest that as many as two-thirds of Tory MPs would like to back Brexit. Many are spending parliament’s recess week agonising over their loyalty to Cameron, what the decision could mean for their hopes of promotion and the extent to which they have previously presented themselves as Eurosceptic to their local parties. Some are even holding public meetings to help them come to a view about which campaign to back.

Ministers have been stopped from speaking out in favour of Brexit until a deal is done because of collective responsibility to back Cameron’s renegotiation strategy. However, four to five cabinet ministers – including Chris Grayling, Theresa Villiers, John Whittingdale and Iain Duncan Smith – as well as about 15 more junior ministers, are likely to throw their weight behind the out campaign within days. Michael Gove, the justice secretary, Boris Johnson, the London mayor, Sajid Javid, the business secretary, and Jeremy Wright, the attorney general, are among those thought to be conflicted.

Backbenchers have had more leeway to say they will campaign for Brexit regardless of the prime minister’s deal. Since Donald Tusk, the European council president, unveiled his proposals in early February, a number of Tories have begun to confirm to their local media or write blog posts about their probable intention to vote to leave the EU. These include three new MPs: Marcus Fysh, in Yeovil, who told his local newspaper he was “leaning towards it being in our best interests to leave”, Andrea Jenkyns, who ousted Ed Balls in Morley and Outwood, who said that “on the balance of probabilities” she would vote out, and Maria Caulfield in Lewes, who said the prime minister’s EU deal appeared to be a token gesture.

Other new MPs to have declared their allegiance to the out camp recently include Anne-Marie Trevelyan, James Cleverly, Scott Mann, Craig Mackinlay, Royston Smith and Paul Scully.

Facebook Twitter Pinterest Andrea Jenkyns ousts Ed Balls in the 2015 general election. She says she will probably vote out. Photograph: Craig Brough/Reuters

Sarah Wollaston, the independently minded Tory MP for Totnes, revealed this week that the lack of meaningful reform in the prime minister’s deal had persuaded her to back Brexit, despite having always thought she would be in favour of staying in.

She said she had worried for hours about the decision, like many of her Tory colleagues. “I am conscious those who back the leave campaign are portrayed as somehow odd or Euro-obsessives,” she said. “But I don’t think that being increasingly sceptical about the EU means that somehow you’re narrow-minded and insular without an internationalist perspective.”

Wollaston said that “an awful lot of people will want to follow the PM’s line to remain whatever the outcome” but she could not back staying in at any cost.

The leave campaign has been battling to win over Tory MPs to its cause for many months, while Downing Street has been trying to induce them to stay loyal and not be swayed by anti-EU feeling in their constituency associations.

Steve Baker, the co-chair of the Conservatives for Britain group of MPs campaigning for an exit, said the past few days had been a time of “sombre reflection” and a “testing time” for his colleagues, who would shortly have to declare for one side or the other.

He said: “MPs are going to have to make a decision soon. I can’t imagine their constituents will let them get away with not saying and they will then have to justify their decisions to the public.”

MPs only have the same vote as everyone else but they would need to make clear their opinion on such a major constitutional issue, he added.



John Redwood, the former Conservative cabinet minister and leave campaigner, this week called on colleagues to be “true to their electors” if they presented themselves as Eurosceptic during the election campaign.

David Cameron suffers setback over proposed EU deal Read more

“Your supporters backed you because they want our democracy restored, with powers of self-government returned,” he said in a message to his colleagues. “They will feel very let down if you do not help them get the UK out of the EU at the referendum.”

In a sign of heightened tensions in the Tory ranks, this prompted an angry reply from the pro-EU MP Sir Nicholas Soames, who told him to “bugger off” on Twitter.

In contrast to the deep Tory divisions on the EU, Labour is more unified. Its leader, Jeremy Corbyn, has expressed reservations about the EU in the past, but the party has collectively agreed to campaign strongly for the UK to stay in the EU. At least 213 of the party’s 231 MPs have signed up for the In campaign, with just four – Kate Hoey, Kelvin Hopkins, Graham Stringer and Roger Godsiff – publicly associated with the Labour Leave group.