Education Secretary Michael Gove has denied claims that his team is behind a briefing campaign against the chief inspector of schools.
It follows a furious outburst by Sir Michael Wilshaw, who revealed he was "spitting blood" over right-wing attacks on Ofsted.
Mr Gove insisted he would sack anyone who had briefed against the education chief and insisted no one in his team had sought to undermine his position.
The Education Secretary said: "Sir Michael Wilshaw is a superb professional and an outstanding chief inspector. He is making the changes Ofsted needs to help raise standards further. No-one working for me has had anything to do with any campaign against him or briefing against him. No one working for me has sought to undermine his position. Anyone who did would be instantly dismissed."
Sir Michael had warned Mr Gove that attacks risked damaging school standards by undermining his authority.
He told The Sunday Times: "I am spitting blood over this and I want it to stop.
"I was never intimated as a headteacher and I do not intend to be intimidated as a chief inspector."
In a fresh statement, he said he was "pleased" that Mr Gove had assured him there had been no campaign run in the Department for Education.
Sir Michael said: " I am proud of my team at Ofsted and seek always to defend them from unfair criticism and those setting out to make mischief. I have talked to the Secretary of State today and I know that he is 100% supportive of my leadership.
"I was very pleased to be assured by the Secretary of State that there are no briefings against Ofsted from the department or people working for him.
"We both therefore hope and anticipate that this is the end of the matter. I am looking forward to continuing to work closely with the Secretary of State to ensure school standards continue to rise."
It comes after reports that the Civitas think tank has urged the Government to create a new body to inspect free schools and academies while the Policy Exchange think tank, which Mr Gove set up in 2002, is calling for evidence from schools about whether the school inspection body is "fit for purpose".
But Civitas chief executive David Green rejected the claims.
He 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."