Headteachers and governors have warned that the borough has run out of places for secondary pupils both in the long and short terms.

The Partnership of Sutton Secondary Schools (PSSS) has been working with Sutton Council on a phased expansion of places, with schools voluntarily expanding in 2015-16 and a new school expected to be built by 2017.

In a letter to council leader Ruth Dombey, Maria Noone and Brenda Morley wrote: “We have now been told that the first new secondary school is being planned for 2018 and may not even be definite.

“We have raised our concerns about future places needed before and we are concerned that the continuing uncertainty around the local authority’s planning for this may lead to a shortage of places for children from 2017 onwards.”

In a reply to the PSSS Coun Dombey said: “We are in a good position to ensure that every pupil in Sutton who wishes to have a secondary school place will receive one next year.

“With respect to the 2017 intake, the projection suggests that there will be sufficient places at year 7, albeit the position is expected to provide less spare capacity.”

In March the council bought a block of land near the old Sutton Hospital for £8m to build a new school by 2017, but the site was rejected as too small by the Education Funding Authority (EFA) and free school provider Greenshaw Learning Trust.

Ruling Liberal Democrats later vetoed a proposal for a free school in Rosehill Park, which the EFA and Greenshaw favoured, further delaying the provision of a new school.

A council spokesman said: “While we value the input of our secondary schools, we do not believe there are any grounds to change this decision.

“We expect the first secondary school to be built on the Sutton Hospital site by September 2018.”