Angry parents are demanding to know why places at high-achieving schools have been cut while class sizes are bigger at more unpopular schools.

The changes are part of Mertons switch from a three-tier form of education to the two-tier primary and secondary system operated by neighbouring boroughs.

Parents say the shake-up has seen reception places at high-achieving, over-subscribed Wimbledon first schools such as Hollymount, Pelham and Dundonald halved to 30, while schools such as Bushey, Hillcross and Stanford have double that number available for fewer first-preference applications. But the council denies there is anything untoward about the situation, claiming the size of existing school buildings has determined class sizes.

Just nine families with reception age children chose Stanford as their first choice school for this September; 13 opted for Hillcross and 24 selected Bushey, according to council figures.

Father-of-two Darren Morris claims the re-distribution of places throughout the borough is a form of social engineering to boost standards at under-subscribed schools.

Mr Morris, of Wimbledon whose son was turned down for a reception place at Hollymount, although he already attends the schools nursery also claims Merton is contravening plans in accordance with the School Standards and Framework Act 1998.

He said it states that surplus places in poor schools were not to be filled by keeping children out of schools that offered higher standards and a better quality of education and claims the re-organisation clearly challenges that directive.

Jonathan Morley, whose twin sons attend Hollymount nursery agreed: "The only places available are where parents dont want to send their children and the LEA are forcing us to do it. Children will move away and into private education.

But head of schools re-organisation Josephine Mahaffey told the Croydon Guardian: It is wholly untrue that we have a policy to cut class sizes in high achieving schools while increasing those at schools that do not have such a high demand for class places.

In many cases schools that are becoming one-form entry primary schools are doing so because the sites are too small to accommodate anything other than one form of entry.

The detailed plans for schools reorganisation in Merton were submitted to the Department for Education and Employment (DfEE) in 1999 and not approved until June 2000, giving the DfEE plenty of time to examine the basis for the distribution of school places around the borough.