The trust that had planned to run a new secondary free school in Rosehill Park has said it and the Government were blindsided by Sutton Liberal Democrats' move to block construction.

On Friday Sutton Council leader Ruth Dombey announced her group would not back the Rosehill option - deemed the most suitable by the Education Funding Agency (EFA) in July - and instead wanted to push for a new school in Belmont, in a building the authority paid £8m for earlier this year.

But that site, near Sutton Hospital, is too small for a school, the EFA believes. Coun Dombey's Lib Dems want to create the school alongside a cancer research centre.

Greenshaw Learning Trust (GLT) said in a statement: "The council told the Department for Education (DfE) and GLT that they would make either site available for the school.

"The Greenshaw Learning Trust and DfE had meetings with officers of Sutton Council and were told that the council would agree 'heads of terms' for the land to be transferred to the DfE for the school at their strategy and resources committee meeting on September 28.

"GLT and DfE had received no prior notice of the council's change of position before the council press statement was released."

A DfE spokesman said: "The Rosehill all-weather pitch site has been identified as the preferred location for a number of reasons including existing sports facilities, retaining the open green space, good transport links and a need for school places in this part of the borough.

"The hospital site would be extremely small for a secondary school meaning any building would have to be multi-storey with limited outside space.

"We consider a range of factors when deciding on a site, including the best outcomes for pupils."

GLT added: "The Rosehill all-weather pitch site would have seen the school built on the derelict all-weather pitch, not on open grassland, and would not have affected the bowling green.

"The only suggestion that any part of the cricket ground should be dug up came from Sutton Council.

"Whilst the council describe the Sutton Hospital site as 'brownfield', building a school there would require the removal of grass and trees - probably more than the proposals for a school at Rosehill."

Yesterday Lib Dem MP Tom Brake demanded his party colleagues explain their decision and how they planned to meet the borough's need for school places without the Rosehill building.