Anti-grammar school campaigners have called for a nationwide study to find out the effects of the 11-plus exam.
Clarke has called grammar schools 'old-fashioned'
Members of the Campaign for State Education (Case) and other groups gave their opinions to education Secretary Charles Clarke at a meeting in London.
They are demanding a comparative study of education achievement in communities with and without grammar schools.
Margaret Tulloch of Case said: "Mr Clarke heard from the people involved that the whole system of selection at 11 is not working.
"We now need the government to commission a survey to see its true effects."
There are currently 164 state grammar schools dotted across several areas of England, such as Kent, Essex, Buckinghamshire and North Yorkshire.
In these areas, around 30% of primary school pupils pass the 11-plus exams.
'Feeling of failure'
Campaigners say this disadvantages the other 70%, who do not make it to grammar school.
An inspectors' study in Kent found that its selective education system had more underperforming schools at tests for 14 year olds than average.
But GCSE results there were above average.
One grammar school head teacher recently said: "We are a centre of excellence, not elitism."
However, another study, carried out in Northern Ireland, recommended the ending of selection at age 11.
When Labour came to power in 1997, it introduced a system of ballots, in which local parents could decide whether to keep their local grammar schools.
The mechanism proved to be complex, with only one ballot being held, in Ripon, North Yorkshire. It went in favour of keeping the grammar school.
'Where is the benefit?'
Tom Royston, who campaigned for its closure, said: "Grammar schools do not raise the performance levels of the most successful pupils, who would have done just as well in a comprehensive.
"But they lower those of the other children are worse. Where is the benefit?
"There is also the social dimension that, for every three pupils who get to grammar school, seven do not.
"So figures showing the success of grammar schools are not a realistic picture.
"They would be the same if every comprehensive looked only at the GCSE results of its top 30% of pupils."
Mr Clarke said in a recent BBC interview: "I and the Labour Party have believed for many years that the 11-plus is an old-fashioned idea. I remain of the view that this is still the case."
He has not, however, committed himself to abolishing selection for secondary schools.