A £29million redevelopment project at The Bushey Academy will transform it into “one of the best schools in the country”, its principal has said.

Members of Hertfordshire County Council's development control committee this week unanimously approved plans to build state-of-the-art classrooms and increase the school's capacity from 1,200 to 1,350 students.

Bushey and Aldenham planning committee had previously given their support to the development, which will now be referred to the Secretary of State for Communities and Local Government.

Internal improvements are expected to begin before Christmas this year, with the major works due to start next Easter.

These include a new games area, car park, a bat roost house.

Some of the buildings, which date back to the 1920s, will be demolished under the plans but those with most historic significance will remain.

During the works, pupils will be taught in temporary classrooms. The multi-million pound project is expected to be completed before the start of the September 2012 term.

The academy, formerly Bushey Hall School, moved to the site on the corner of High Street and Falconer Road in 1989. It had previously been known as Grange Park School.

In a document attached to the report presented to the county councillors on Tuesday, it was suggested that the existing buildings were the “most prominent cause” of the school's poor performance throughout the last 20 years.

According to Ofsted reports, they are “unsuitable for modern teaching methods, are a contributory cause of poor behaviour, and are disjointed, inflexible and difficult to manage”, the document said.

It added: “The academy programme provides a unique opportunity to ensure that future generations of young people attending the academy are not disadvantaged and deprived of the chance of a good education as their predecessors have been.”

Andy Hemmings, principal of The Bushey Academy, which opened in September 2009, said he was delighted the project had won unanimous approval from both planning committees.

He said: “The new building, which replaces all existing teaching spaces with state-of-the-art facilities and even includes a pioneering science 'Mega-Lab', will make the academy, in my opinion, one of the best schools in the country.

“For four terms we will move into modern, light and spacious temporary facilities on site, with the new building opening alongside the retained halls in September 2012, when the current Year 6 students enter Year 8.

“The building development, alongside the significant improvements we have made here, has already led to enquiries from parents about how to secure places for their children at the academy in the future.

“I want to re-assure everybody that we are, and will continue to be, a local school for local children and that we will continue to ensure that every child that comes here realises their full potential.”