Ed Miliband launches cross-party alternative vote push
Labour leader Ed Miliband has joined top Liberal Democrats including ex-leader Charles Kennedy to call for a change to the system for electing MPs.
Green Party leader Caroline Lucas and Lib Dems Baroness Williams and Tim Farron also joined Mr Miliband to call for a Yes vote in 5 May's referendum.
But Lib Dem leader Nick Clegg was not invited - after Mr Miliband refused to share a platform with him.
It came as the No campaign urged voters not to ditch "one person one vote".
Mr Miliband has urged Nick Clegg, who also supports a change to the alternative vote system, to "lie low" during the Yes campaign, given public anger with Mr Clegg over student tuition fees and public sector cuts.
But he refused to comment further on the deputy prime minister's enforced absence from the Yes campaign event.
"I have said what I have said about Nick Clegg... This referendum mustn't be about political parties, it is not about a referendum about Nick Clegg or a referendum on David Cameron, it is about whether you want a new voting system."
Mr Kennedy refused to comment on Mr Clegg's absence, but Lib Dem president Tim Farron said: "The Labour Party will want to make points about Nick and that is fair game."
But he added: "It would be wrong to get into silly rows about who should or should not be on the platform. I am not going to get into that."
Mr Clegg, who is on a trade and diplomatic mission to South America, later referred to the voting issue in a speech to the Mexican Parliament.
He said the government "was split on the best voting system for the UK" but both coalition partners agreed that "it was up to the people to decide".
Labour MPs are split on whether the current first-past-the-post voting system should be scrapped, with senior figures such as former cabinet members Margaret Beckett and John Prescott campaigning for a No vote.
But Mr Miliband urged all those on the centre-left to unite behind the push for the alternative vote.
"The tragedy for progressive politics historically has been that division on the centre and left has handed a united right victory after victory," he said.
"For most of the last 80 years, there has been one Conservative Party - but several competing for progressive votes. The result, over the years, speak for themselves.
"No wonder the Tories back the current system. They know Britain is not a fundamentally Conservative country. But with first-past-the-post, they too often govern when progressive forces are divided... Britain deserves an electoral system that fairly reflects voters' views."
'Gang of nine'
Mr Miliband was joined by shadow cabinet colleagues Tessa Jowell and John Denham, who both made speeches urging a Yes vote, with Mr Denham claiming AV was an "anti-extremist system which... enables the progressive majority to come through".
Mr Miliband and the others laughed off suggestions from journalists that the cross-party campaign was the start of a new coalition or, as Mr Miliband jokingly dubbed it the "gang of nine" - a reference to the founding of the SDP, when Baroness Williams was a member of a "gang of four" breakaway Labour politicians.
Caroline Lucas, in her speech, said "two party politics is dead, it's finished", adding that "people vote differently now and we therefore need a voting system to reflect that".
She acknowledged that she would have preferred a "properly proportional electoral system" but AV was "a significant improvement on first-past-the-post" and a "no vote would set back the debate for electoral reform for at least a generation".
Mr Kennedy, in his speech, told people who wanted to wait for a more proportional system "you can't afford that luxury".
"This is the proposition on the table. This represents the force of political reform and this is the chance that has got to be seized."
But former Home Secretary Lord Reid told BBC News AV was a "threat to the very basis on which we have always held our democratic system".
The Labour peer said AV "completely undermines and corrupts" the principle of "one person one vote", claiming it would allow voters who support "minority parties" such as the BNP to have more of a say in election results than the supporters of mainstream parties.
Asked if he would join Conservative leader David Cameron on a No to AV platform, he added: "This issue is much bigger than any political party... I will share a platform with anyone who stands for safeguarding the right of the people of this country to have equal votes."
And, in a letter to the Times on Tuesday, four former foreign secretaries claimed the current system was an example to other democracies.
"Those of us who have represented Britain internationally know one of the many reasons why we have always punched above our weight in the world is our simple and straightforward voting system," the signatories - including Labour's Margaret Beckett and Tories Malcolm Rifkind, Lord Hurd, Lord Howe and current foreign secretary William Hague - argued.
Under the current Westminster electoral system, voters place a cross next to their preferred candidate. Under the alternative vote they would rank candidates in order of preference.
If no candidate wins more than 50% of the vote the candidate with the fewest votes is eliminated and their backers' second choices allocated to those remaining, with process continuing until one candidate has more than half the votes in that round.