A STUDY of London's status as a hub for international travel will consider options including expanding Heathrow Airport via the construction of four new runways above the M25 motorway, in addition to long-standing plans such as an island terminal in the Thames estuary.
Options for upgrading Heathrow, hemmed in by housing on three sides and London's ring road on the west, will be fully explored as the Airports Commission seeks ''plausible'' ways of adding capacity, its chairman, Sir Howard Davies, said.
''The government has made it clear that we can relook at those options,'' Sir Howard said in London on Friday.
The construction of a third runway at Heathrow to the north would be evaluated, Sir Howard said, with more novel options such as linking Cardiff Airport in Wales to London via a high-speed rail line. The plan to expand Heathrow to the west, proposed last month by the Policy Exchange research group, entails building three-kilometre runways over the M25 and Wraysbury reservoir, reducing the impact on housing.
Heathrow attracted 69.4 million passengers last year and is operating close to capacity. The Policy Exchange initiative would increase the limit to 130 million people a year.
Stewart Wingate, chief executive officer at Gatwick Airport, the busiest in the world with a single runway, said his site south of London was ripe for development. ''A new runway at Gatwick could be more affordable and practical than other options.''
The Conservative mayor of London, Boris Johnson, also opposes any new runway at an existing site and favours construction of a new hub on a sandbank in the Thames estuary.