More than 300 GM schools nationally are expected to lose 510 teachers and 333 non-teaching staff.
It follows new research conducted by the Open University that concluded GM schools, which were introduced by the Conservative party 10 years ago, had not raised standards and had not been good value for money.
Graham Lane, education spokesman for the Local Government Association, said: 'GM schools have finally woken up to the fact that they have lost the extra bribe they used to have. They should realise that money was taken away from other schools in the first place.'
The TES survey claims only eight GM schools are to return to full local authority control. The rest are to become foundation schools, the option closest to their present status.