The government is expected to make a decision this week on whether to back Heathrow or Gatwick for a new runway.
According to a report in the Sunday Times, a subcommittee of 10 cabinet MPs will meet over the next few days, with the long-awaited decision expected to come out in favour of Heathrow.
In July, The Airports Commission recommended the government expand Heathrow with prime minister David Cameron promising a decision by the end of the year.
Cameron had previously said that “no ifs, no buts” there will be no expansion at Heathrow.
A decision to back Heathrow could cause splits in the Conservative party – MP and London mayoral candidate Zac Goldsmith has threatened to quit if the west London hub receives backing.
Chairman of the Hacan Clear Skies campaign group, John Stewart, said: “If the decision is for a third runway at Heathrow, it wouldn’t be a surprise given the way the subcommittee has been stacked with cabinet members who support expansion of Heathrow.”
Click here to see images of Heathrow with a third runway.