The BBC's Andy Tighe: "The pro-comprehensive lobby has been planning its campaign for years"

Speaking at a rally organised by campaigners trying to win support from parents in Ripon, North Yorkshire, he said that if those in favour of academic selection were so confident of its merits, they should allow ballots on its future.

But he said that grammar school supporters already knew they had lost the argument, because hard evidence "demonstrates conclusively that selection offers no extra academic benefits to gifted children and cruelly disadvantages many other students".

Lord Hattersley, who himself attended a grammar school, is well known as a leading critic of selective education.

Grammar supporters 'afraid of losing'

Campaigners in Ripon want to trigger a ballot on changing admission arrangements at Ripon Grammar School.

Lord Hattersley is a well-known opponent of selective education

To do so, they need 20% of eligible parents to sign a petition, which means they need just 700 signatures from parents at the school's 18 feeder primary schools.

In other areas where selective education is more widespread, more signatures are needed. To end selection in Kent, which has more than 30 grammar schools, campaigners need to collect 40,000 signatures.

Petitions have also been launched to try to trigger ballots in Trafford and the London boroughs of Barnet and Sutton.

At Thursday's rally, Lord Hattersley said those who were opposed to ending selection were attempting to stop a ballot taking place, because they were afraid they would lose.

Ripon Grammar School is one of the oldest grammars in England

"Our sole aim is the creation of an education system which meets the needs of all our young people - that writes off no one as rejects, that offers no one inferior status and reduced opportunity, that does not diminish self-esteem and confidence and therefore wastes talent the nation cannot afford to lose," he said.

"We know that secondary selection is arbitrary and shamefully inaccurate in its record of measuring a child's ability and potential.

"It was in that knowledge that Margaret Thatcher presided over the creation of more comprehensive schools than any other Secretary of State for Education."

"The success of comprehensives comes from their all-ability intake. All we ask in Ripon is that entry requirements should be adjusted to make that success possible."

Fighting back

But those in favour of grammar schools argue they are assets which should be kept as they are.

The battle over grammar schools looks set to continue for a long time

Nick Seaton, Chairman of the Campaign for Real Education, has appealed to parents in Ripon not to sign the petition, as he said it would make no difference to the quality of other schools in the area.

He said: "It is a nonsense to undermine a system that is working.

"What needs to be done is for schools that aren't performing well to be brought up to the standard of the best, not to undermine high-achieving schools."