Normally, church schools, which are often oversubscribed, have to meet 15 per cent of the cost of building extra classrooms.
But a pounds 40m package for 600 extra classrooms agreed in the March Budget will ensure that they and other popular schools receive the full cost of expansion. Names will be announced later this week.
The Prime Minister has promised that no pupils in the five-to-seven age group will be in classes larger than 30 by 2001. Ministers are anxious that the class-size pledge should not lead to children being denied places at popular schools and diverted to those with empty places.
David Willetts, the Conservatives' education spokesman, said the class size policy was "a disaster in the making".
"What seemed like a good idea with the focus groups is turning into a disaster in the classroom," he said. "Labour will only be able to achieve their pledge by depriving parents of the chance to send their children to the school of their choice. There is also a risk of more mixed-age classes."
The pledge to cut class sizes using money from phasing out the assisted places scheme is one of the Government's main commitments.
Stephen Byers, the school standards minister, said Mr Willetts could not make up his mind whether he was for lower class sizes or against them. "From a party which presided over 10 years of rising class sizes, this is no surprise.
"Labour will deliver its class-size pledge and we will do so in a way which benefits pupils and parents, respecting parental preferences and underpinning our drive for higher standards in the three Rs."Reuse content