Many high profile MPs face a battle for electoral survival after the boundary review revealed sweeping changes to England's parliamentary constituencies.
Changes will see the Commons cut from 650 MPs to 600 and constituencies redrawn to ensure they have between 72,810 and 80,743 voters.
Among the MPs thought to be at threat are Ken Clarke, Chris Huhne and Tessa Jowell.
Shadow cabinet members Ed Balls and Hilary Benn could face a battle for one seat while chancellor George Osborne's Tatton constituency will disappear.
However the proposals are not certain to be accepted, with some Labour MPs accusing the Conservatives of gerrymandering and a number of senior Liberal Democrats said to be unhappy at the prospect of losing parliamentary seats.