Objections to selective admissions policies have been lodged with a government adjudicator in Hertfordshire, Surrey, Torbay, Essex, Lancashire and the London boroughs of Wandsworth, Bromley and Croydon.
The objections are the opening salvos in the campaign to get rid of the country's 166 grammars - two of which are already destined to become comprehensive.
Decisions are expected by the end of July from Sir Peter Newsam, the chief adjudicator of admissions, and his 16-member team charged with resolving local disputes. Sir Peter can step in and order school admission rules to be re-written.
Nearly 50 complaints have been lodged with the chief adjudicator from parents and local education authorities. They concern grammar, grant-maintained and voluntary-aided schools.
Parents of primary-school children may object to selection by ability, while authorities may object on that and other grounds.
Some schools have been accused of introducing new ways of selecting by ability. Objectors have also said that selection by aptitude is unfair.
Three-quarters of the objections come from Hertfordshire and Surrey, which have large numbers of selective schools and grant-maintained schools.
But with a new Conservative administration, Hertfordshire may yet change its policy and attempt to withdraw its opposition.