Hornsby House School in Balham is saving on space by building new dining rooms and catering facilities underground.

Two thirds of its ground-breaking new building project will stretch out underneath the playground, it was announced this week.

Developers claim the project fills an awkward corner of the school site while keeping space for children’s playtime.

The building is due to open in time for the summer term.

A school spokesman said: “Hornsby House is absolutely thriving. There are motivated, happy and high-achieving children gaining an impressive range of awards at senior school entry.”

The school is also launching scholarship and bursary scheme aimed at bright children whose families would not otherwise be able to consider private education.

There will be three scholarships for Year 4 pupils - two academic and one for a bright child who is also talented in music or sport.

Bursaries up to 100 per cent of fees will be available.