An 80-year-old school will be completely rebuilt if multi-million pound plans are approved.

St John's School, in Stock Road, Billericay, could soon be transformed with a new sixth-form, more classrooms and a new sports hall as part of a "green" development.

The private school's principal, Joanne Osen, described the project as a "dream" put together over 18 months.

She said: "We will see more spacious classrooms, more laboratories and improved facilities throughout. It would be environmentally-friendly with biomass heating, solar energy and special green walls with plants growing over them."

She also said the downward slope of the grounds meant the building would stand only as high as an ordinary house.

Fiona Armour, the headteacher for 14 years, said: "We are very excited. This would be a new era for the school,which has grown up from just seven pupils to 460 today.

"This will mean we can continue excellent teaching with much improved facilities and lovely environment. The pupils are also excited and are keenly viewing the plans.

"At the moment pupils must leave at 16, but we would like the option to stay on into the sixth form."

Plans include:

* A three-storey, 24-classroom block to be built at the back of the grounds

*A sports hall

* Two new drama areas, one of which will be open-air

* Office and administrative areas with a staff meeting area called the royal box with views across the school

* Grassy and hard play areas.

The project is possible after the school, which currently caters for children aged three to 16, bought the freehold of the site from previous owner, St John's College, Oxford.