Stansted Airport has begun work on a £40 million project to extend the main terminal building.

The 36m by 162m development will double the size of the immigration hall, provide space for more baggage carousels, add 5,900 square metres of floor space to the international arrivals area and introduce better retail and onward transport facilities.

As part of the work, 22 diagrids - forming the roof - and six support trees will be installed.

Biomass boilers burning renewable forms of fuel to generate hot water for direct use and heating will also be fitted.

The extension is due to open in June 2008 and be fully complete by December 2008.

Uttlesford Council granted planning permission for the work in 2002 as part of the application by the airport to handle 25 million passengers per year.