Image copyright PA Image caption Michael Gove (left) appointed Sir Michael Wilshaw in January 2012

The chief inspector of schools in England has accused staff at the Department for Education of briefing against his organisation.

Sir Michael Wilshaw spoke after the Times said two right-leaning think tanks were to criticise Ofsted - and one would call for it to be scrapped.

He told the Sunday Times he was "spitting blood" and blamed Michael Gove's department for briefing on it.

A source close to Mr Gove said no-one close had encouraged the attacks.

As long as we exist and have the job of raising standards, we will do the job fairly without fear or favour Sir Michael Wilshaw

The two think tanks both confirmed they were working on reports on Ofsted, but denied their work was being done with encouragement from the Department for Education.

The Times on Friday reported that Policy Exchange - which was set up by the education secretary - and Civitas were preparing to call for a radical overhaul of the Ofsted inspection regime, claiming it was trapped by 1960s "progressive" approaches to learning.

It said Civitas would say Mr Gove's wish for schools to develop their own approaches to teaching was being held back by child-first orthodoxies among inspectors, who were stifling innovation.

Policy Exchange, the paper said, would say the current inspection regime placed disproportionate pressure on teachers, while its judgments were too inconsistent.

Sir Michael told the Sunday Times he suspected the think tanks were being "informed by the Department for Education" - "possibly" Mr Gove's special advisers - and that he was "displeased, shocked and outraged".

Analysis Opponents used to talk about "the Two Michaels", such was the assumed unity of purpose between Sir Michael Wilshaw and Michael Gove. Teachers' unions routinely accused the Ofsted chief of lacking independence from the education secretary. But this row, in the shadows of briefings and think tanks, suggests some of the fault lines. Apart from Sir Michael's hackles being raised by the criticism of Ofsted, he is sending a signal about his intentions not to give any special treatment to academy chains or free school providers. Sir Michael, a former academy head teacher, has said the chains which run groups of academies must be open to scrutiny by Ofsted, in the way that local authority services can be inspected. This Ofsted boss has turned around tough schools. He's been there, done it - and in his case, not so much got the T-shirt as got the crisp suit and tie. And no one would doubt his single-mindedness or willingness to challenge vested interests if he believes it will raise school standards.

"I am spitting blood over this and I want it to stop," he said.

Asked whether he wanted Mr Gove to call off the "attack dogs", the newspaper reported, he replied: "Absolutely."

He added: "It does nothing for [Michael Gove's] drive or our drive to raise standards in schools.

"I was never intimidated as a head teacher and I do not intend to be intimidated as a chief inspector."

'Another think coming'

Sir Michael, who inspects children's services as well as schools in England, was appointed by the coalition and he and Mr Gove have been thought of as allies.

Sir Michael has also drawn criticism from teachers' unions in the past , and defended his organisation, saying it had done "more to raise standards in 21 years of existence than any other organisation".

He also said that in parts of the country no-one was effectively monitoring free schools and academies, the newspaper reported.

"If I see things going wrong in an academy chain I will say so," he said.

"If people tied to the free-school movement think I will not do that, they have another think coming."

Image copyright PA Image caption Ofsted is being accused of being stuck with a 1960s mindset over teaching

"As long as we exist and have the job of raising standards, we will do the job fairly without fear or favour."

Sir Michael also expressed his concern at right-wing critics of the education system who, he said, wanted "children to be lectured for six hours a day in serried ranks".

Such rote learning, he said, was not enough to produce successful learners in the 21st Century.

A source close to Mr Gove told the BBC it definitely was not the case that the education secretary or anyone near to him had encouraged the attacks.

But shadow education secretary Tristram Hunt accused Mr Gove of "playing politics".

"Michael Gove should not seek to discredit Ofsted because Ofsted has given negative judgements to under-performing free schools," he said.

"Michael Wilshaw is right that there is a complete lack of local oversight of free schools to prevent the sort of failure Ofsted has identified."

'Misguided notions'

Civitas director David Green said: "The idea that Michael Gove is in any way directing our criticism of Ofsted is well wide of the mark.

"We have had serious misgivings about Ofsted for many years, driven by the testimony of teachers and their concern for school standards.

"The fact is, whatever Sir Michael Wilshaw's intentions, we know schools that would like to innovate are scared to do so because of the misguided notions of many Ofsted inspectors. It would not be in Michael Gove's power to 'call off' our criticism whether he wanted to or not."

A spokeswoman for the Policy Exchange confirmed that it too was working on a report on Ofsted, but said: "We haven't been told to do that and if we were we wouldn't."