A group of senior Labour politicians will help spearhead the campaign for a "no" vote in next year's referendum on changing the voting system.
Former cabinet ministers John Prescott, David Blunkett, John Reid and Lord Falconer have signed up as patrons of the "NO to AV" campaign while Margaret Beckett will be its president.
They will join forces with a raft of Tory Cabinet ministers, including Foreign Secretary William Hague, Justice Secretary Ken Clarke and Education Secretary Michael Gove.
The heavyweight line-up is a significant boost to efforts to persuade the country to vote against switching from first-past-the-post to the alternative vote (AV) system for general elections.
Allowing a public vote - due to be held on May 5 - was a key concession won by the Liberal Democrats as part of coalition negotiations with the Conservatives.
Labour promised a referendum on AV in its manifesto and the change is supported by new leader Ed Miliband, but MPs have a free vote on the issue and there is significant Labour opposition.
The senior figures will speak publicly for the campaign as well as acting as advisers. Labour former minister and party vice-chair Joan Ryan will be the campaign's deputy director and another former minister Jane Kennedy is national organiser.
Ex-foreign secretary Mrs Beckett said: "This is so important it has to rise above party politics.
"Only three other countries use AV and one, Fiji, is abandoning it. It led to a significant drop in the number of people voting in Australia - that's why they had to make voting compulsory. AV doesn't help democracy, it stands in its way."
Lord Prescott attacked the referendum as a "shoddy little deal that the Lib Dems made with the Tories as their price for power" and Lord Reid said there was "no credible intellectual or political case that can be made for AV".