Nick Clegg was accused of opportunism after the deputy prime minister announced his party wanted to end Michael Gove's ideological experiment and require all free schools and academies to be subject to the national curriculum. Clegg, speaking in the wake of the Al-Madinah free school in Derby being labelled dysfunctional by Ofsted, also announced he opposed the continued employment of unqualified teachers.

The tenor of Clegg's remarks appear to clash with the enthusiastic support for unqualified teachers in free schools expressed by the Liberal Democrat schools minister David Laws last Thursday in the Commons.

Laws had said unqualified teachers were doing a superb job in schools, and said the best backstop to teaching quality was not formal qualifications, but Ofsted inspections.

The Tories, surprised by Clegg's intervention, accused him of undermining Laws, and in a statement from the Department for Education insisted the policy on freedoms for free schools and academies would remain unchanged.

Clegg insisted his announcement, due to be set out in a speech on Thursday, did not create a political crisis, and was a reflection of a difference of opinion.

"Of course there are tensions and pinch points and it is not a crisis when some of these differences are articulated in private," he said. "It is a longstanding fact that we think differently."

Senior Conservatives on Sunday night said they were convinced Laws had not been warned of the policy shift on Saturday night. However, Clegg's office said Laws, a close adviser to the Liberal Democrat leader, had been closely involved in the speech that reflected Liberal Democrat policy passed in a motion at their spring conference this year and for which Clegg had voted. Laws made no mention of the policy in his speech to the main Liberal Democrat conference in September.

Clegg insisted that he had aired his support for reimposing the national curriculum privately within the government, and that Laws's defence of unqualified teachers in the Commons on Thursday had merely reflected his ministerial duty to represent the government's education policy.

This was ridiculed by Conservative sources who said that in private Laws, far from wanting to constrict the freedoms enjoyed by academies, wanted to extend them to all schools. The Tory sources also said the Liberal Democrats had let Labour off the hook over their year-long muddle on whether to support free schools .

Jeremy Browne, sacked by Clegg as Liberal Democrat minister in the Home Office, expressed his concern with his party's policy shift.

"I don't think we should be instinctively statist and I don't think we should be instinctively in favour of the status quo. I want us to have a restless, radical, energetic, liberal reforming instinct that is about putting more power and responsibility and opportunity in the hands of individual people".

Speaking on Sky's Murnaghan programme, Clegg said that he was a great supporter of free schools and accountability.

He added: "As we move to an era of greater autonomy and schools have greater freedoms to decide things for themselves, we at the same time have to ask them to respect certain basic quality standards so that parents, regardless of where their son and daughter go to school, can be reassured that their children are going to be taught by qualified teachers [and] they are going to be taught the national curriculum like in any other schools."

Clegg said: "There are three positions here. The Labour party position would want to strangle school autonomy. They have always wanted to micro-manage schools. The Conservative party does want the minimum amount of basic standards and I in a sense support a sensible balance.

"Yes, give schools more autonomy and yet give reassurance, regardless of whether the school is called a free school or an academy [that] children are taught by a qualified teacher to the same standard as any other school in the country."

Clegg's stance brings the Liberal Democrats closer to the Labour party position on the accountability of free schools and academies. It also makes it more difficult for him to sustain the attack on Labour's position on free schools as muddled.The DfE insisted it would not backtrack on existing policy. A spokesperson said: "Free schools are raising standards and giving parents more choice. They 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.

"Independent schools have always been able to hire brilliant people who have not got QTS [qualified teacher status]. Free schools and academies now have the same freedoms as independent schools to hire great linguists, computer scientists, engineers and other specialists so they can inspire their pupils."