Campaigners in Kent, Barnet and Ripon have registered with the Electoral Reform Ballot Services. They intend to start the petitions needed to trigger ballots on ending selective admissions to local grammar schools. They have until July 2000 to collect sufficient names.
The Campaign for State Education, which is backing the parents, is also issuing a Say No to Selection pack to guide groups through the complex ballot rules.
Meanwhile, John Bercow, Conservative education spokesman, has described CASE as left-wing activists and egalitarian hooligans. He said: "The ballot regulations have almost as many holes as a packet of Polo mints and Conservatives will fight to protect the excellence of schools that left-wing vandals yearn to destroy."
He said there was a risk of fraud because the signatures do not have to be witnessed.
Campaign groups will need to get their petitions signed by 20 per cent of eligible parents to trigger a ballot. In mainly selective areas all parents will be entitled to vote. In areas where there are only a few grammar schools only parents of pupils at feeder primaries will have a vote.
Anti-grammar school groups are also organised in Trafford, Sutton and Medway.
CASE says it was saddened by Mr Bercow's attack, saying it was strictly non-party political. Its president, Joan Sallis, was given an OBE by John Major.
Its spokeswoman, Margaret Tulloch, said it was insulting to both parents and the ballot services to suggest that the petition process was open to fraud. She said the ballots were more complicated than those needed for schools to opt out.