Economy of London project is construction of 42 km (26 mi) of new tunnels connecting stations in central London including a branch to Canary Wharf in east London. It is Europe's biggest construction project with a £15 billion projected cost. An additional line, Crossrail 2, has been proposed. London is served by six international airports which are the world's busiest city airport system by passenger traffic. These are Heathrow, Gatwick, Stansted, Luton, London City, and Southend. There are a number of proposals for expanding airport capacity for London including expansion of London Heathrow Airport and expansion of Gatwick Airport. The principal argument in
London Britannia Airport London Britannia Airport London Britannia Airport is a proposed six-runway airport to be built on an artificial island in the River Thames estuary to serve London, comparable to a similar approach taken with Hong Kong International Airport. The proposal had been dubbed "Boris island" by the media, reflecting the support for the project from former London Mayor Boris Johnson. The scheme was proposed by Testrad (Thames Estuary Research and Development), initially an agency formed by Johnson but now also involving other partners, and was rejected by the airport commission in January 2014. Plans for a Thames Estuary Airport go back