The Government has announced sweeping reforms of Britain's democratic institutions.
Deputy Prime Minister Nick Clegg said a proposed boundary review, equalising the size of all but two constituencies, will be in place in time for the 2015 general election.
Mr Clegg also confirmed that a referendum on replacing first-past-the-post Westminster elections with the Alternative Vote system will be held on May 5 next year.
He said that legislation on the boundary review would pave the way for the process to be completed by 2013, in time for the selection of candidates ahead of the next General Election poll on May 7, 2015.
The number of MPs is to be cut from 650 to 600, saving around £12 million a year on pay, pensions and allowances.
A majority of two thirds will be needed to carry a vote for the dissolution of Parliament, rather than the 55 per cent first suggested.
Flanked by Prime Minister David Cameron, Mr Clegg said these "profound changes" are necessary to "clean up politics" and restore trust in the political system.