Conservatives spoke out after a senior party figure was sent to Belfast seeking a deal that could have seen the DUP handed ministerial jobs, with one Tory telling The Independent it meant being “pushed out to the right”.
In the end, no formal coalition was agreed. But a “confidence and supply” arrangement was struck for the DUP to back the Tories on key votes. The Cabinet will discuss it on Monday.
It came as Ms May was also forced to let go of her two trusted aides Nick Timothy and Fiona Hill – described as her “right and left arm” – to prevent a leadership challenge following her disastrous election campaign.
The Prime Minister then came under pressure from the Scottish Conservative leader Ruth Davidson, strengthened by Tory success north of the border, who called on her to think again about leaving the EU single market.
The resignations will buy time for the Prime Minister, but she is still fighting for her political life amid a growing belief in Tory circles that she must go after a period of months as an “interim leader”.
Strikingly, her Cabinet again failed to come out publicly to support her and her planned reshuffle had to be postponed amid the turmoil.
Graham Brady, the chairman of the Tories’ backbench 1922 committee, is thought to have personally demanded the heads of Mr Timothy and Ms Hill to prevent an immediate leadership contest.
Meanwhile, Gavin Barwell, who lost his Croydon Central seat at the election, was quickly appointed as Downing Street’s new chief of staff, bringing “considerable experience” to the post, the Prime Minister said.
As the twin chiefs of staff quit, Gavin Williamson, the Conservative Chief Whip, was in Belfast, pushing for the 10 DUP MPs to enter into a formal coalition agreement, rather than simply propping up the Government on key votes.
It appeared Ms May had decided she needed the strength of coalition to bolster her chances of keeping her Government alive, amid growing pressure from angry Tory MPs and members.
No 10 said the chief whip was exploring “how best they can provide support to the Government”. A source confirmed to The Independent that coalition was on the table.
However, it was thought the DUP was wary of coalition, given the miserable fate of the Liberal Democrats after entering government with the Conservatives.
Later, a No 10 spokesman said: “We can confirm that the Democratic Unionist Party have agreed to the principles of an outline agreement to support the Conservative Government on a confidence and supply basis when Parliament returns next week.
“We welcome this commitment, which can provide the stability and certainty the whole country requires as we embark on Brexit and beyond.”
It would mean the DUP backing the Government on its Budget and other key votes and – crucially – preventing it being brought down by motions of no confidence.
Neil Carmichael, a former select committee chairman who lost his Stroud seat last Thursday, said: “The DUP has the potential to push the Conservative party out to the right.
“On Brexit, I have argued that we need to come back to the middle, including people who voted to Remain. This has to be about where Britain goes – not just a chunk of Britain.
“And there’s Northern Ireland itself. The Government is apparently brokering a return to Stormont, but how can it if it has some of the politicians in its own camp?”
A former minister, Ed Vaizey, highlighted the danger of any DUP tie-up, saying: “I come from liberal wing of the Conservative party.
“I’m not going to support any legislation that I would regard as socially illiberal, or taking this country backwards.”
Sarah Wollaston, chairwoman of the health select committee, insisted that any deal with the DUP must not be allowed to influence policies on the death penalty, gay rights, education or abortion.
“I will always support the right for women to choose & access safe termination of pregnancy & will oppose any change to the legislation,” she tweeted.
“I will never agree to any dilution of LGBT rights. Creationism in schools? Hell no.
“If any of that is a condition of confidence and supply it simply won’t work.”
Alex Maskey, a Sinn Fein member of the Belfast Assembly, said a deal could “prove to be reckless” for Northern Ireland, adding: “The British public should have full scrutiny of the DUP and what that party represents.”
Earlier, Ms Davidson, who is gay, revealed she had demanded assurances from the Prime Minister over gay rights should the Tories do a deal with the DUP.
She again challenged her leader when she refused to say that Britain should pull out of the EU single market, as Ms May wants.
Instead, she said: “There’s an awful lot of issues surrounding Brexit that need to be discussed. Clearly, there is no majority government that’s come through after this election.
“That means we do have to listen to the other parties and that means we have to listen to others actors and agents – and that is exactly what we will do.”
Meanwhile, a survey by the ConservativeHome website further undermined the Prime Minister by revealing most Tory members want her to resign after her election failure.
Almost 60 per cent of grassroots Tories said the Prime Minister must fall on her sword after destroying her Commons majority.
Outside the Downing Street gates, anti-DUP protesters chanted “Tories out, refugees in” and “Tories out, Corbyn in”, as a petition against a deal between the two parties topped 500,000 signatures in just 12 hours.
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