If the ballot on the future of Ripon Grammar School is won by the pro-grammar campaigners, their opponents are likely to stage an appeal against the voting rules.

Although refusing to concede that they have lost the ballot, campaigners against selection are angered by the "grossly unfair" way in which eligibility to vote has been determined.

And Debbie Atkins, spokesperson for the Ripon Campaign for State Education, says that there are enough parents concerned by the rules on voting to trigger an appeal.

In particular, those seeking to end the grammar school system in Ripon will question how over a quarter of the electorate was drawn from parents of pupils at two private, preparatory schools outside of the town and another private school in Ripon.

"Only 5% of parents in north Yorkshire have children in prep schools, but in this ballot they have 26% of the vote," says Debbie Atkins of the Ripon Campaign for State Education.

If as anticipated these prep-school parents vote overwhelmingly in support of retaining grammar status, the pro-grammar lobby will only have to win a third of the remaining electorate to gain a majority.

Debbie Atkins and the anti-grammar campaigners are angry that this could mean that a clear majority of Ripon parents could vote against selection, but that they could still lose the ballot.

In order to gain a simple majority, the anti-grammar lobby is likely to need to win over two-thirds of the votes of parents at state primary schools in Ripon.

The ballot is intended to represent the wishes of parents whose children will be affected by the future status of the school - which in effect means the parents of 'feeder' primary schools.

In the regulations, a feeder school is defined as any school which has sent five or more pupils to the grammar school in the past two years.

Campaigners against selective education say that this gives an in-built advantage to grammar schools, because it increases the likelihood of private schools being counted as feeder schools.