Pauline Latham, chairman of the Grant-Maintained Standing Advisory Committee, said the private sector “where tests are tougher for, say, Eton or Harrow than they are for a minor public school” could be the model. “As schools become more popular they may want to change the sort of test they run. Parents will then have a choice of the sort of school they want their child to go to. Parents are more sophisticated than they are often given credit for and will become attuned to the tests which are on offer.”

Others in the GM sector, like Mrs Latham, doubted that last week’s White Paper would do much to increase the number of grammar schools. They believe there is not a groundswell of support for selective schools.

But Mrs Latham said: “Selection is something parents can understand more than opting out. Many parents wouldn’t question the decision to opt out, but I think they will question the selection decision more because they can remember it from their childhood.”

The National Grammar Schools Association describes selection nationally as a patchwork quilt. Local authorities with many grammar schools, for example Buckinghamshire and Kent, run admission tests. The most common are those prepared by the National Foundation for Educational Research.

In Bucks, children take three verbal reasoning papers and the average marks of the best two are used for the score. Those who score 121 and above (out of a maximum of 141) secure a grammar-school place. It costs the education authority Pounds 57,500 to administer.

Grant-maintained schools can set their own exams, for example, Small Heath in Birmingham which can select 10 per cent for technology, requires children to design a boat from paper. In practice, however, they too use NFER tests.

Local authority technology colleges (schools which have raised Pounds 100,000 to be matched by the Government) abide by their authority’s admissions criteria. The GM Chaucer technology school in Kent has been approved to select all its pupils by aptitude. It sets up three “learning experiences” (for example, watching a video) which can be the basis for interviews which will determine entry.

Headteacher Jim Wynn said: “We choose purely on technical aptitude. But, as we are in an area with grammar schools, we may use the White Paper if it becomes law to set aside a grammar-school stream to make the intake a fully comprehensive range of ability.”

Eamonn Harris, head of Queen Elizabeth’s boys’ school, in the London borough of Barnet, believes fears about selection should not be based upon the old two-tier system. He said: “In the old days children who failed the 11 plus were offered a watered-down grammar-school curriculum. Today . . . modular courses would allow pupils flexibility between A-levels and vocational qualifications. ”