Johnson said Gatwick was "not a long-term solution" and expanding Heathrow "would create unbelievable levels of noise, blight and pollution". The mayor, who wants to run for parliament in next year's general election and is rumoured to have ambitions to replace Prime Minister David Cameron as Conservative leader, also argued a new airport to the east of London would create "jobs and growth". A final political decision is only due by the end of the next parliament, which would be in 2020, and construction is planned to be completed by 2030. The aim is to retain London's status as the world's top international air travel hub.