Zac Goldsmith, Conservative MP and environmental campaigner who has threatened to quit over a third runway at Heathrow, told BBC Radio 4's Today programme:
"We haven't just lost Justine Greening from this department, we have also seen Theresa Villiers moved out, both of whom were absolutely rock-solid on this issue in terms of defending what is still the Government's line officially.
"I think their movement out of the Department of Transport shows the Government is at least trying to open the door to the possibility of a third runway."
More top news
Every Christmas gets a bit more desperate for one dog at Battersea. Can you help?
The problem has meant that no trains are able to run through Gatwick Airport rail station in West Sussex.
Schoolchildren found Eragon wearing a Christmas jumper in the bag filled with dog food, treats and a tear-jerking note, in a church.