Airport operator BAA today announced a £980 million expansion plan for Gatwick Airport to cope with an expected air travel boom.

It is part of a ten-year, £8.1 billion investment programme at London's three main airports.

The programme assumes air traffic will double over the next 20 years.

The programme includes £6.6 billion for Heathrow airport in west London, £980 million for Gatwick and £600 million for Stansted in Essex, where a £60 million terminal extension opened today.

BAA's chief executive Mike Hodgkinson said: "The investment is essential if Britain is to have the quality airports it needs."

The plan does not take into account any extra runways that could be built.

Government options for airport and runway capacity are to be published shortly, to be followed by an aviation White Paper which is expected to contain firm policy.

The BAA plans for Gatwick include:

Segregation and improvements to piers and work on stands - £80 million South Terminal arrivals extension and pier 1 development - £60 million;

North Terminal level 3 extension and pier 6 - £80 million, a new mid-airport satellite - £250 million, and car park improvements - £65 million.

The BAA plans envisage passenger numbers at Gatwick rising to 42 million using the existing two terminals and one runway.

However BAA added today that forecasting Gatwick growth was very difficult and that the full investment programme would be reviewed during the course of the year.