The U.K. government gave its approval on Jan. 15 for a third runway and sixth terminal at London’s Heathrow airport. Construction is estimated at $13.5 billion, and a rail hub also could be built at the airport providing high-speed links to London and central England. The project has proved controversial with many opponents, including the Conservative Party, challenging the scheme on environmental grounds. Transportation Secretary Geoff Hoon says measures to reduce the environmental impact include limiting the runway’s early use and allowing access only to the “cleanest planes.” Because of the urgent need, he says permitting will begin soon for construction to end after 2015. Some 700 homes just north of the airport must be demolished to make way for the project. In parallel with Heathrow’s expansion, there is a plan for a high-speed railroad hub that London-based Arup Group Ltd. estimates will cost $6.7 billion.