Earthworks on Sydney's second international airport are due to start next year after the federal government committed to building the $5 billion project.

Prime Minister Malcolm Turnbull has described the airport, to be constructed at Badgerys Creek, as “a vitally important project for western Sydney, for Sydney and the nation”. The government’s commitment came after Sydney Airport Corporation, which operates the existing Mascot airport, walked away on Tuesday. The airport has been spoken…