Almost one in five children in England is still affected by the 11-plus nine years after Labour promised to end selection, according to a group backed by more than 100 of the party's MPs.
Every year about 60,000 pupils take the 11-plus or watch their classmates do so, according to evidence to the commission which will approve policy for Labour's next manifesto.
The evidence was presented by Comprehensive Future, a group of Labour members, councillors and MPs which wants selection by ability and aptitude abolished if the party wins a third term.
At Labour's 1995 conference, David Blunkett, then shadow education secretary, promised: "Read my lips: no selection, either by examination or interview under a Labour government." But the pledge was dropped by the party even before it came to power in 1997.
After seven years of Labour, there are now more children facing selective entry tests than under the Conservatives, Comprehensive Future says.
At the moment, 15 local authorities are fully selective and a further 21 have some grammar schools.
In addition, specialist schools can select up to 10 per cent of pupils by aptitude, although the Government says few actually use this power.
Earlier this year, a Parliamentary petition calling for an end to selection was signed by 106 Labour MPs.
Margaret Tulloch, secretary of Comprehensive Future, said the 164 remaining grammar schools rejected three times as many pupils as they accepted.
"The streets of north London are blocked by cars when the three grammar schools in Barnet hold their entrance tests.
"You have to look at the effect of the whole system and its effect on the children who fail to get into grammar schools as well as those who succeed," she said.
Charles Clarke, the Education Secretary, reopened the debate about selection in 2002 when he asked inspectors to report on the performance of the largest selective local authority, Kent.
But Prime Minister Tony Blair is expected to block any promise to end selection, fearing it will be seen as an attack on excellence and alienate middle-class parents.