A residents' group has welcomed the decision by Sutton Liberal Democrats to block construction of a new secondary school in Rosehill Park - but questioned why the site was ever considered for the project.

Last Friday council leader Ruth Dombey revealed her group would veto attempts by the Education Funding Agency (EFA) to build the new free school at Rosehill, after the agency rejected the council's preferred site in Belmont.

Both sites were presented to the EFA to consider after a feasibility report commissioned by Sutton Council.

A new secondary school will be needed by 2017.

Chris Carter, secretary of the Sutton Garden Suburb Residents' Association, said: "It was a ridiculous idea in the first place. No sensible or civilised society is going to start building on its precious park land.

"I want to know why it was the council ever thought about Rosehill park in the first place."

Mr Carter said he recognised the urgent need for more secondary school places in the borough, but that "building on a park isn't a solution".

He added: "I think this situation could have been avoided if the planning put into it was started a bit earlier and carried out a bit more rigorously.

"A secondary school is not something you suddenly realise you need.

"We pressed the council very hard and put forward some logical reasons why this is not a good site for a secondary school. Maybe they were persuaded by us."

In July the EFA chose Rosehill's derelict all-weather pitches as its preferred site for a new free school.

It deemed the council's favoured option, the former Sutton Hospital site the authority bought for £8m in March, too cramped.

The Friends of Rosehill Park community group launched a petition in August opposing a school in the area.

It reads: "Even for the local community that does not share the use of this excellent park, the traffic in and around this area will be massively impacted.

"We all appreciate the need for school places that serve the borough of Sutton, but there are already two secondary schools within 10 minutes’ walk of the park."

The Greenshaw Learning Trust (GLT), which would administer the new free school, said: "The council told the Department for Education and GLT that they would make either site available for the school."