David Cameron has called for an immediate general election, saying the political system has been "paralysed" by the expenses scandal at Westminster.
The Tory leader urged people to sign a petition calling on Gordon Brown to dissolve Parliament and hold a poll.
He said he would use the Tory campaign for Euro and council elections on 4 June to call for a general election.
He said people could not wait another year to "pass judgement" on Parliament, as trust in politics was "in pieces".
Mr Cameron was speaking just minutes before unprecedented scenes in Parliament where the Speaker faced direct calls from MPs for a parliamentary debate on his future.
The Conservative leader urged party supporters campaigning in next month's European and English council elections to start collecting signatures for a petition calling for an immediate general election.
There's no point doing what David Cameron suggests, which is having an election where you change a few faces but keep the old rules in place
Nick Clegg Lib Dems
"I want as many people as possible, whether you support Labour or the Lib Dems or no party at all to join in," Mr Cameron said.
"Write to your local paper, write to a national newspaper - start your own petition. From the power of our collective pressure we can force Gordon Brown to act."
An election should be held at the earliest possible date after 4 June, Mr Cameron said, to enable the public to pass its verdict on the expenses crisis gripping Parliament.
The political system had been left in crisis by the revelations about MPs' expenses, he said, and trust in politics was "frankly, shot to pieces".
"I don't think the country wants to wait another year to pass judgement on their politicians and this Parliament," he said.
Mr Cameron has asked all Tory candidates for the European Parliament to sign a pledge on their conduct, requiring them to publish details of all their office, travel and staffing costs as well as their contacts with lobbyists.
He said this was a "first essential step" to cleaning up politics.
Asked about the election call later, Liberal Democrat leader Nick Clegg said it was no good trading in one "tainted government run by an establishment party" for another establishment party.
"There's no point doing what David Cameron suggests, which is having an election where you change a few faces but keep the old rules in place," he said.
"I think we need much, much bigger change in this country than the superficial point-scoring by David Cameron."
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