Justine Greening has been replaced by Patrick McLoughlin as Transport Secretary in todayâ€™s Government reshuffle.
Vince Cable continues as Business Secretary, one of five Liberal Democrats who keep their posts in the coalition cabinet.
Greeningâ€™s outspoken opposition to a third runway at Heathrow is widely seen as the cause of her move to the post of International Development Secretary and is dominating todayâ€™s debate about the reshuffle.
Other issues, such as Greeningâ€™s plans to overhaul the quality of the MOT system, are not yet on the agenda.
Former miner and Conservative McLoughlin is thought to have no objection to the plan which has prompted London Mayor Boris Johnson to describe the job moves as â€˜madâ€™.
Johnson said in a statement: â€œThe third runway would mean more traffic, more noise, more pollution – and a serious reduction in the quality of life for hundreds of thousands of people.
â€œAnd it is time for the government to level with Londoners. Are they in favour of a third runway at Heathrow or not?”
Transport Minister Norman Baker, however, has said it would be wrong to assume the move out for Greening as meaning automatic support for a third Heathrow runway.