The future of free schools was up in the air today, after an explosive attack on the project from Nick Clegg triggered confusion in the Liberal Democrats and a retaliation from allies of Michael Gove.
In a public criticism of the initiative which took Conservatives by surprise, Clegg briefed Sunday newspapers on a speech to be given next Thursday in which he will say the schools need to have qualified teachers, abide by the national curriculum and satisfy certain food standards.
"Whilst I want to give schools the space to innovate, I also believe every parent needs reassurance that the school their child attends, whatever its title or structure, meets certain core standards of teaching and care. A parental guarantee, if you like," he said.
"What's the point of having a national curriculum if only a few schools have to teach it?"
The interjection follows a damning leaked Ofsted report into the al-Madinah free school in Derby last week which criticised the quality of teaching and raised concerns about the safety of children.
It also comes after the resignation of a free primary school head teacher, who was still studying for her postgraduate certificate in education when she took the role.
Clegg's interjection is being interpreted in some quarters as an appeal to Labour, in a bid to prepare the ground for a possible coalition with the opposition after the next election.
Clegg branded that theory "complete and utter nonsense".
He added: "It's not a political crisis when some of those differences are articulated in public."
Shadow education secretary Tristram Hunt, who has made many of the same criticisms of the free schools programme, offered a cautious welcome to Clegg's speech.
"Michael Gove and David Cameron's divisive Free Schools programme is unravelling for all to see," he said.
"But Nick Clegg is locked-in to this failure too. It is his policies that have led to the mess we saw at the al-Madinah free school earlier, the looming crisis in teacher recruitment and the 141% rise in unqualified teachers since 2010."
The comments also sparked questions within the Liberal Democrat party, especially since Lib Dem education minister David Laws – a close ally of Clegg – had been allowed to make precisely the opposite point about free schools on Thursday when responding to an urgent question on the al-Madinah school.
"There are plenty of teachers who may not have formal qualifications but who still do a superb job." he said at the time.
Lib Dem sources insists Laws was involved in the Clegg speech and that his comments last week reflected the need for him to take government responsibility over policy.
Jeremy Browne, who was recently demoted from his ministerial job in the Home Office and is suspected in some quarters of planning a move over to the Tories, spoke out against his party leader.
"I support free schools. I am interested in how we can innovate, how we improve our educational outcomes in this country," he told the BBC's Sunday Politics programme.
Speaking on Radio 4 this morning, climate change secretary Ed Davey said Clegg was outlining the party's plans for the next election.
"When you're a government minister, you defend the government line. But a party leader talks about our manifesto. He's got to put those policies forward," Davey said.
"Nick for a number of months now has been making it clear there's a difference between the Liberal Democrats and the Conservatives in a number of areas."
The Conservatives were somewhat taken aback by the coordinated attack over the weekend, but they launched a robust response this morning, with education minister Elizabeth Truss saying it was a "shame" Clegg has changed his position on free schools.
The "whole point [of the schools] is they have these freedoms," she added.
"That's what's helping them outperform maintained schools.
"You shouldn't kill off the goose that's laid the golden egg."
Conservative education select committee chair Graham Stuart told the Today Programme."The classic liberal view is trusting the front line and allowing them to make the decisions.
"I thought they believed in localism, yet here we are at the first sign of trouble and Nick Clegg comes over all Barbara Castle. It's a very peculiar approach."
Stuart accused Clegg of an opportunistic lurch to the left.
"I guess we'll see more of this as we approach the general election but I think it would be better if Nick Clegg decided to have differences with the Conservatives, if he did so on the basis of liberal policy rather than a lurch to the left."
Other government sources were far more scathing, saying Clegg's name had become "a byword for cheap sanctimony, opportunism, gimmicks and lying".
A Downing Street spokesperson highlighted the discrepancies between Clegg's comments and Law's argument in the Commons last week, while allies of education secretary Gove said the deputy prime minister was guilty of "fundamentally misunderstanding" free schools.
A Department of Education spokesperson said: "Free schools are run by teachers – not local bureaucrats or Westminster politicians – and are free to set their own curriculum, decide how they spend their money and employ who they think are the best people for the job.
"This government is not going to take these freedoms away."
Recent polling has shown that Liberal Democrat supporters are deeply sceptical of the coalition's education policies.
YouGov found that current Lib Dem supporters were far more than twice as likely to back Labour's education policies than the Conservatives.