One of Medway’s biggest schools wants to downsize drastically because it can no longer fit in its “cramped” classrooms.

The Robert Napier School, Gillingham, has revealed plans to reduce its pupil intake from 240 last year to 150.

The move comes despite several primary schools expanding ahead of an expected population surge, which will hit secondaries in about six years.

A consultation statement said: “The school has expanded over the past eight years and we are now struggling to accommodate all students in the highest standards.

“The main building, which was created in 1929… is currently cramped with narrow corridors and small classrooms, not designed with the classes of today in mind.”

More pupils are choosing to stay on for sixth form, the report added. Six years ago there were 30 sixth formers studying three courses – now there are 150 studying 20 courses.

Head teacher Fiona Miller said the school had been “top of the list” in the government’s axed Building Schools for the Future programme.

“We’re surrounded by new academies that do have new-builds and greater capacity that isn’t currently being used,” she added.

Some of Napier’s 1,400 pupils have to take PE and dance classes at a primary school, and staff struggle to fit in exam desks for GCSEs and A-levels.

Medway’s secondary schools have more than 400 spare spaces, but that number is set to plummet when a bubble hits of at least 300 extra pupils.

But Medway Council’s cabinet member for schools, Cllr Mike O’Brien (Con), said: “I don’t think it’s going to make too much of a difference.

“We’ve made plans to expand our primary school places and when the secondary school bubble comes up we’ve got plans in place for that.”

Napier has already reduced its intake to 210 this year and, if approved, the cut to 150 will take effect in September 2015.

Priority will be given to children of staff, children in care and those with a sibling at the school.

• A consultation runs until December 31. To comment email admissions@robertnapier.org.uk