The Conservative Party has been committed to decreasing the number of MPs and we have now seen the recommendations on the changes to constituency boundaries (with loss of several Parliamentary seats). The full set of reports can be found here (at Guido Fawkes's Blog).
Unsurprisingly, Labour seats seem to be the biggest losers followed by the Liberal Democrats. If these changes had been in place before the previous general election, then it is likely the Conservatives would have won a majority.
UPDATE: Richard Moss has the latest analysis on changes for the North East here. Items to note is that Hexham will become the largest constituency in England -- and Sedgefield and Whitley Bay will become easier targets for the Conservatives. Sedgefield's most famous MP was Tony Blair, so perhaps the end of a longstanding safe Labour seat in the heart of Co. Durham?
UPDATE 2: The BBC notes here the MPs that may be most affected by these changes, including Hilary Benn (Lab), Vince Cable (LD), Ken Clarke (Con), Chris Huhne (LD), Tessa Jowell (Lab), Caroline Lucas (Green), Chuka Umunna (Lab), and - interestingly enough - George Osborne (Con).
UPDATE 3: Now we learn that many senior politicians from all three major parties - including Vince Cable (Lib Dem) - have voiced opposition to these proposed changes. Details here.