Theresa May's confidence and supply deal with the Democratic Unionist Party (DUP) has been thrown into turmoil today as reports emerge suggesting the DUP will vote with Labour in blocking Tory plans to hike tuition fees to nearly £10,000 later this afternoon.
The party's MPs will vote with Labour in favour of a "fair pay rise" for NHS workers and against the government's rise in tuition fees - the first time they will have broken with the Conservatives since their deal after the election.
The DUP, integral to Theresa May's coalition government, is also expected to vote with Labour and block hikes in student fees later on Wednesday.
"Lifting the cap on nurses' pay and in the public sector generally is our party policy".
Janet Davies, General Secretary of the Royal College of Nursing, said: "The Government saw the strength of opposition and backed away to avoid defeat".
She said: "We have a constitutional crisis because this Government is running scared and not allowing votes in this House".
The DUP's decision to side with Labour on both of these bills will nearly certainly mean a defeat for the government, but Tory MPs are being advised to abstain in an attempt to lessen the impact of any defeat.
"It's not part of our confidence-and-supply arrangement".
Conservative sources said they were "pretty relaxed" about the outcome of the debate as it does not require the Government to change policy.
It comes the day after ministers effectively ended the pay cap with the announcement of rises above the 1% limit for police and prison officers.
But the move, announced on the same day figures showed the inflation rate had reached 2.9%, did little to ease the criticism of the Government's pay restraints.
Earlier, DUP MP for North Antrim Ian Paisley said: "I must say that myself and my colleagues are minded to support the motion. put before the House this evening".
"We welcome the Prime Minister's commitment to flexibility on the pay cap".
For Labour, shadow health secretary Jonathan Ashworth called on ministers to make clear whether they meant to ignore the "clear will of the House" or take action to end the pay cap in the NHS.
During the debate Health Secretary Jeremy Hunt labelled the Labour motion as "bogus" and said it was "absolute nonsense" to suggest the cap over the last seven years was part of an "ideological mission" to reduce the size of the state.
"And is it also not clear that the reason the Government did not divide on this motion is they knew they would lose?"