Inspections of private schools are to be toughened up, with a significant increase in the use of no-notice and shorter-notice checks under plans being drawn up by the government.

Officials said the move to reduce the warning time before an upcoming inspection had been designed to bring the independent sector into line with the system used in state schools. The new regime will apply to the country’s most high-profile public schools as well as smaller, private faith schools.

The Department for Education (DfE) has been pushing the independent sector to change its inspection regime and originally suggested that it adopt the same criteria used by Ofsted. That plan has now been dropped but the private sector is instead being urged to cut the notice period given to schools, which is currently four or five days. Headteachers in the sector have hit back, describing the proposal as “unrealistic”.

State schools are typically told of an impending inspection on the day before they are due to be visited. The use of no-notice inspections has also increased recently, with 40 carried out last month in the wake of the “Trojan Horse” allegations relating to Islamic extremism in Birmingham schools.

Sir Michael Wilshaw, Ofsted’s chief inspector, has said he will make greater use of no-notice inspections if concerns arise about safeguarding, rapidly declining standards, the curriculum, leadership or governance.

Some 2,400 private schools currently operate in the UK and Ofsted inspects half of them. But more than 1,200 of the country’s biggest and best-known private institutions, including Eton College and Cheltenham Ladies College, are inspected by the Independent Schools Inspectorate (ISI).

Under the ISI’s current system, a team of serving headteachers and senior staff “peer review” schools under the leadership of a professional inspector. The notice period of five days allows for confidential questionnaires to be completed by students and parents and for “conflicts of interest” to be declared before the inspection takes place, according to headteachers.

In a letter to the Independent Schools Council associations, Peter Swift, deputy director of the DfE’s independent education and school governance division, said: “We will be asking the independent inspectorates to come forward with proposals for reducing the notice period for inspections and greater use of no-notice inspections as the need arises.”

But Matthew Burgess, the outgoing general secretary of the Independent Schools Council, whose members are inspected by ISI, said: “It would alarm us if the notice period was reduced so much that the peer review process could not take place.”

He said there was “absolutely no evidence” that ISI inspections were not rigorous enough. Ofsted’s annual review of ISI offered “high praise for the standard and effectiveness of ISI’s inspection process”, he added. In terms of safeguarding, he said, ISI inspectors were in schools for twice as long as Ofsted so judgements were “likely to be more testing”.

Richard Cairns, headmaster of Brighton College, said that increasing the use of no-notice inspections risked placing a “psychological burden” on headteachers. Shortening the notice period from five days would also create problems, he said.

“I don’t think anyone would mind an inspector coming in and going into five lessons but bringing the paperwork together and making it accessible to inspectors takes time,” he added.

“It’s unrealistic to give schools less than five days to do this. You can’t turn your school around in that time but you can have the paperwork together.”

A spokesman for the ISI said the organisation was researching ways of getting good feedback from student and parent questionnaires with a shorter notice period. “It is important to us that this vital element is not diminished,” he said. “This key feedback informs the shape of ISI inspections and ensures that the voices of pupils and parents are heard and acted upon.”

The inspectorate already undertook unannounced inspections on behalf of the DfE when “particular concerns, especially about safeguarding issues, have been raised”, he added.

The planned changes will also affect the Bridge Schools Inspectorate, which checks institutions belonging to the Christian Schools Trust and the Association of Muslim Schools, and gives five days’ notice before visits. The School Inspection Service, which inspects Steiner Schools and schools run by the Plymouth Brethren Christian Church, is also in discussions with the DfE about reducing its four-day notice period.

The tougher regime for private faith schools comes after complaints last month when three of the 10 state-funded Jewish schools received surprise visits from Ofsted in two weeks.

Rabbi Jonathan Rabson, chief executive of the National Association of Orthodox Jewish Schools, told The Jewish Chronicle newspaper that they were being unfairly targeted. “We are very concerned about the recent spate of unannounced inspections of Jewish schools, which are way out of proportion with no-notice inspections in other faith communities,” he said.

`Peer inspection is a massive benefit’

Kevin Fear, headmaster of Nottingham High School, said: “Schools need to be ready for inspection at any time so it might not make that much difference. Where it wouldn’t work so well is that you need all the school’s senior team there. If we only get half a day’s notice, then you can’t guarantee they will all be there to give the right impression. It’s practicalities such as this that mean I am a bit concerned.

“One of the massive benefits of the current system is that it is peer inspection. It is unclear to me at this stage whether with a shorter period this will still be really possible.”

He added: “We do send out questionnaires to our parents regularly and it is also part of the inspection process. One would hope that if we had no-notice then we would still be allowed to feed in the results of these surveys.”