As part of the campaign to target "coasting schools," ministers argue that many grammars are not stretching their academically able pupils.
The schools they will be targeting are mainly mixed grammar schools that opted out of local education authority control.
David Normington, head of the Department for Education and Employment schools directorate, told a meeting of Kent headteachers last week: "We need to focus not simply on the low performing schools, but on those which are coasting.
"I am talking about schools where the results are sufficiently good to avoid the annual round of questioning that arises from performance tables, and about the schools which are just good enough to avoid trouble from the Office for Standards in Education. I am talking about schools which, on the basis of intake, must be able to do better."
He told the heads that new value-added performance data would expose "complacent" schools and questioned why any grammar could not ensure that 90-100 per cent of its pupils got five or more A to C GCSEs.
A TES analysis of results shows that 8 per cent of the 166 grammar schools in England fall below Government expectations. They are in Bristol,Cumbria, Gloucester, Kent, Lincolnshire, Stoke on Trent, Trafford and the Wirral. In 20 grammar schools, all pupils gain five or more high-grade GCSEs.
The focus on coasting grammars comes as the campaign to scrap them was formally launched this week. Under new legislation, parents can call for a ballot on the future of the local grammar school.
Leading left-wing barrister Michael Mansfield has criticised the Government for not abolishing the schools outright. The lawyer for the Stephen Lawrence family said the Government should be supporting multi-racial, all-ability schooling.
Last weekend Mr Mansfield, who has six children, attended a "No to Selection" meeting in London, addressed by former Labour minister, Lord Hattersley.
Mr Mansfield told The TES: "It should be a basic human right to receive an education that does not depend on private money or the ability to pass the 11-plus."
Most grammar schools - 60 - are in the South-east. Of the rest 20 are in the South-west; 19 each in London, the West Midlands and the North-west; 15 in the East Midlands, eight in East Anglia and six in the North.
The new push by ministers was welcomed by heads in Kent, where there are 33 grammars and where anti-selection activists have already leafleted parents.
Specialist schools expansion,7