Highgate councillors have taken their battle to save a former school site from being sold off for housing to the secretary of state for education.

Pupils at Ashmount School are due to move from their building in Hornsey Lane, Highgate, to a new school site in Crouch Hill, Crouch End, next year.

It is feared the old building will be converted into social housing after Islington Council changed its planning policy to state that the building is “surplus to requirements as primary and nursery teaching facilities”.

But councillors over the border in Haringey, where many children historically go to Ashmount, have warned that losing the building will heap more pressure on the shortfall of primary places in Highgate.

Highgate Cllr Rachel Alison said: “Once that site is lost it will never be gotten back, no matter how many children need a place.

“Islington Council says it has no need for more places and I’m willing to believe them. But it has failed to look at whether this can be used for secondary or higher education.

“And here in Haringey there is a big shortage of primary places. One borough is loath to interfere in another’s business, but this is literally five yards away.”

Councils must get the secretary of state’s approval to change the use of education buildings for other purposes.

Islington Council is expected to publish a planning application for the site in the new year.

Cllr Paul Convery, Islington’s planning chief, said the closure would not lead to a loss of places.

He said if more children moved to the borough, other Islington schools have the capacity to expand.

He said: “We are moving an existing school, so it is not like we are closing the school and losing those places.”