A referendum on introducing the alternative vote (AV) system for Westminster elections is to be held on 5 May next year, the government has announced.
On 5 July 2010, Deputy Prime Minister Nick Clegg said the poll will be held on the same day as local elections in England and elections to the devolved legislatures in Scotland, Wales and Northern Ireland - saving £17m in costs.
"The question will be simple - asking people whether they want to adopt the AV, yes or no," he told MPs.
If people voted for a new voting system, the 2015 general election will be held using it and according to new constituency boundaries, he added.
Mr Clegg also revealed that a Commons majority of two thirds will be needed to carry a vote for the dissolution of Parliament, rather than the 55% first suggested.
But he pledged that a general election would be held if a government lost a confidence motion by a simple majority and an alternative government could not be formed within 14 days.
Shadow justice secretary Jack Straw said the proposal to abandon the 55% vote required for dissolution of Parliament was "the first major U-turn of this government".
"Why didn't you think before about the implausibility of a government hanging on after it had lost a vote of no confidence by a simple majority?" he asked. "It would have saved you a great deal of embarrassment."
But he argued that the two-thirds vote would be "completely superfluous".
Mr Straw added: "Either you are in favour of fixed-term parliaments as long as the government of the day enjoys the confidence of this House or you are not."
A succession of Tory backbenchers criticised the government's planned referendum date and Plaid Cymru's Elfyn Llwyd said it smacked of "contempt".
The statement also provided further detail on plans for fixed-term parliaments, and to review constituency boundaries to create "fewer and more equally sized" seats.
Mr Clegg revealed that the number of MPs would be reduced from 650 to 600, and not 585, as previously suggested.
The shadow justice secretary described this as the "most arbitrary and partisan of all his proposals".