The boarding school, where children can choose whether or not to attend lessons, has been given six months to improve standards or be closed down by the Department for Education.

The school has launched a campaign to save the school while maintaining its "alternative values".

On Wednesday, three coachloads of pupils joined other supporters at Whitehall to symbolically "bin" the school's report from the Office for Standards in Education (Ofsted).

They held a demonstration, and handed in their petition, addressed to the Prime Minister, Tony Blair, protesting at its threatened closure.

School's challenge

In May, Education Secretary David Blunkett filed a formal notice of complaint about the school following the Ofsted report.

The notice means the school, in Leiston, will have to close if it does not raise standards in the next six months.

The Ofsted report is "binned"

But the school says it will challenge the parts of the notice of complaint which require it to "compromise its educational and philosophical aims, and which undermine the basis upon which it is founded".

It also says that if the parts of the notice which undermine its philosophy are not withdrawn, it will appeal against the notice to the Independent Schools Tribunal, and if necessary, pursue the matter to the European Court of Human Rights.

The co-educational school, where the fees range from £5,300 to £6,550, was founded in 1921 by A S Neill, the father of its current head teacher Zoe Readhead.

Pupils vote on school rules

It has been built on principles of allowing children greater independence over how they learn. The school says that it intends to "create a happier childhood by removing fear and coercion by adults".

Each week, a meeting of pupils and staff decides on the running of the school, with adults and children each having a single vote. This governs such matters as bed times and behaviour rules for the 61 pupils, who are between the ages of eight and 18.

Zoe Readhead: "Closure threat is ludicrous"

Ofsted's highly critical report focuses on the school's policy of allowing pupils to choose whether or not to attend lessons. It says this has led to some pupils not attending maths lessons for two years.

But Ms Readhead said: "It is ludicrous that a unique educational experiment like Summerhill, that has been recognised throughout the world as a valuable educational resource since 1921, should be threatened with closure.

Unlikely ally

"A Summerhill education fosters democratic values, participation and co-operation, and promotes critical knowledge, cultural awareness and social understanding.

"This prepares its students to participate in society as active creative members of the community. It should be allowed to continue to flourish on its own terms."

One unlikely ally of the school to emerge since the publication of the Ofsted report has been Baroness Blatch, the Conservatives' education spokeswoman in the House of Lords.

She told the House of Lords that parents had a right to choose to send their children to the school, which had exam results above the average for state schools and very high levels of support from parents and pupils.