Gatwick could expand ahead of Heathrow under plans being drawn up as the airport is prepared for sale, putting fresh pressure on the government to postpone its decision to build a third runway at Heathrow.

Transport secretary Geoff Hoon is due to decide on a third runway in late January after the government repeatedly postponed a decision this year.

Gatwick was put up for sale this month as owner BAA fights a break up ordered by the Competition Commission. The Times reports BAA has sent potential bidders a memo showing the position of a new runway at the airport, which would expand capacity from 45 million passengers a year to 80 million.

Work on the runway could start in 2019 when a 40-year agreement with local authorities to cap expansion expires.

The government has already given the go-ahead to a new runway at Stansted and the revelation threatens to intensify opposition to airport growth.