Governors have denied claims there are serious problems at a school where the head resigned suddenly last week as teachers and parents seek an explanation.

Sarah Mackintosh’s departure from Rosebery School, in White Horse Drive, Epsom, on the last day of term caused shock and surprise to parents and pupils at the school.

Parents were told on Friday via ParentMail, the school's electronic communications system, that Ros Allen, the deputy headteacher was taking over as acting head leaving the school, which has around 1,470 pupils, without a permanent head until January.

No reason has been given for Mrs Mackintosh’s sudden departure expect that she has decided to "move on in her career" - but it is highly unusual for heads to give less than two terms notice.

She did not even say goodbye to the girls at the successful school which she has run for five years - fuelling widespread speculation as to the underlying cause.

On Friday evening, John Strutt, chair of governors, said: "Sometimes people make decisions quickly and feel they need to act on them quickly. She made a personal decision to move on."

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Sarah Mackintosh

Governors have insisted they had no hand in her leaving and denied rumours that the school is in financial difficulty, that staff were unhappy with her leadership style and that the number of teachers had been cut.

Mrs Mackintosh received high praise in the school's 2013 Ofsted report for her "relentless determination to focus on continuous improvement in the quality of teaching."

But the inspectors said "a period of significant change in senior leadership roles has meant that the pace of change has not been fast enough" and it warned that the senior leadership team needed to be strengthened "so that roles and responsibilities are manageable and can be sustained."

The school became an academy two years ago, giving the management team greater control over the school budget and teachers’ salaries and removing the local authority’s ability to influence what happens there.

Following the announcement last Friday, it emerged that Ms Allen had taken over the running of the school on March 14, but John Mitchell, vice-chair of governors, said this was only because Mrs Mackintosh suffered from a "severe migraine".

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Ros Allen

On Saturday the article was the fifth most read article on Newsquest’s websites around the country as parents and pupils shared it on Facebook.

Two serving teachers at the school, who insisted on anonymity for fear of reprisals, and four former staff members are among those who have contacted the newspaper saying that the full story has not come out and explaining what they believe has contributed to Mrs Mackintosh's abrupt departure.

A number of people alleged that the school is in financial difficulties pointing to the school's annual report for the year that ending on August 31, 2013, which showed that the school spent £373,078 more than its income.

Mr Strutt said Government funding is being cut to schools in general, adding: "We are seeing less money coming in."

But Mr Mitchell said: "We are carrying forward surpluses in all years. There is no problems at Rosebery with finances. None at all." A spokesman at the Department for Education said: "We don’t have any current financial concerns with Rosebery School."

Other people claimed that staff were unhappy that the number of teachers was being cut at the school.

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According to the last governor’s annual report for the year ending August 2013, the average monthly number of teachers had already fallen from 89 in 2012 to 81 in 2013, but support staff had increased from 40 to 51.

But Mr Mitchell said staff numbers fluctuate all the time and said: "I can assure you we have not reduced staff in that period."

However, he confirmed reports that in the past few weeks staff have been asked to consider taking voluntary redundancy.

He would not reveal how many staff they wanted to lose but said it was a "very small number".

He said all schools review their staffing structure and have to respond to financial pressures and changes to the curriculum nationally.

He said: “That’s nothing to do with Rosebery. It’s the Government driving all this.”

Mr Mitchell insisted that asking staff to take voluntary redundancy was a routine measure and not linked to financial difficulties.

He said: "We do that regularly. Every school constantly sends out letters regarding the restructuring." Nick Trier, from teachers’ union NASUWT, said this week: "The school has undertaken a couple of consultations on change to the staffing structure to make some savings."

One former teacher claimed a recent staff survey showed that a majority of staff had lost confidence in Mrs Mackintosh's leadership, adding: "Staff morale is really, really low. It’s the best thing ever that she left, staff are elated."

But Mr Mitchell denied this, saying the governors had carried out a routine survey and the only concerns raised were over general operational matters, not the school leadership.

He said: "Ninety-seven percent said they were extremely proud to work at Rosebery."

He added: "We are a very well managed school. We are going to continue to get better and better."

Another former staff member told the Epsom Guardian: "I have friends among the long-serving staff who are unhappy and feel bypassed."

James Barnett, who taught at the school for three years until 2012, said he liked Mrs Mackintosh but was not totally surprised that she had gone, linking her departure to the school receiving a good, rather than an outstanding, rating at its Ofsted inspection last year.

He said: "Mrs Mackintosh is a victim of over-bearing pressure from above to be 'outstanding' - pressure that is just not needed, in my opinion, because Rosebery is an outstanding school.

“Mrs Mackintosh put a lot of pressure on the staff to perform at updated and in my opinion, non sustainable Ofsted teaching standards. This made her rather unpopular with some staff."

One of the teachers called for the resignation of both the chairman and vice chairman of governors saying they needed to take responsibility for what has happened: "They have let the school down, they have let students down and they have let parents down.

“The whole thing is a flaming mess."

But Mr Mitchell said there was no responsibility for governors to take and no cover-up.

Attempts were made to contact Mrs Mackintosh to allow her to comment without success.

Rosebery has been praised as one of the top 100 performing non-selective state funded schools in the country for two years in a row.