The Liberal Democrat leader, Nick Clegg, who is in discussions with the Tories' David Cameron over forming a government, has been told firmly that there must be 'no sell out over PR'.
The call came in a series of loud chants and demands from over 1,000 protesters gathered outside the temporary Liberal Democrat negotiations HQ in Smith Square, London, yesterday afternoon (8 May 2010).
Mr Clegg found himself making an impromptu speech to the crowd after receiving a large public petition calling for fair votes from Pam Giddy, the coordinator of Power 2010.
The demonstration was one of several across the country. Earlier, some 2,500 people had gathered in the capital's Trafalgar Square to demand electoral reform through a proportional voting system.
The protests have been called through the Take Back Parliament coalition (www.takebackparliament.com/hope ), which includes Power2010, Unlock Democracy, the Electoral Reform Society, Vote for a Change, Ekklesia, Friends of the Earth, Greenpeace, the New Economics Foundation, the Fawcett Society (which campaigns for women's equality), Operation Black Vote, Hang 'Em (http://hang-em.com/ ) and others.
Clegg was greeted with enthusiasm - but also concern and questioning - by the purple-clad crowd, with those calling for change adopting the colour of the suffragettes.
“It’s in the interests of everybody in Britain for us to use this opportunity to usher in a new politics after the discredited politics of the past," the Lib Dem leader said.
But in neither this speech, nor in other interviews throughout the day, did he specifically mention either "electoral reform" or "proportional representation" - leading many to fear that Mr Clegg is about to make a compromise too far in order to grab a slice of power for himself and his party.
Those on both the left and right of the party, including Simon Hughes and David Laws, were keen to dampen speculation that a specific commitment on PR would be essential to a deal with David Cameron - whose party implacably opposes it.
Reformers, including many who voted Lib Dem to help achieve a hung parliament, are furious at the idea that Mr Clegg will abandon the principles he vaunted so loudly in the campaign, all the time accusing the "old parties" of refusing real change.
“There are no deal-breakers in the negotiations and that would include PR as well,” said one MP who was at the meeting, according to the Times newspaper.
Billy Bragg, the singer and activist, and one of those involved in galvanising the Take Back Parliament movement, said: “We don’t want Clegg to do a deal with any party that can’t guarantee proportional representation.”
The fair votes protests, which will continue across Britain this week, are historic in nature.
"This is probably the first time a party leader has spoken to a demonstration without actually having been invited to address it beforehand," observed Anthony Barnett wryly.
Barnett, a writer and academic, was a founder of Charter 88, and more recently has been a key player in the Hang 'Em campaign for a balanced parliament, as well as other grassroots democracy initiatives.
Take Back Parliament's petition (www.takebackparliament.com/hope ) is rocketing towards 40,000 in just a couple of days, and as the Conservatives and Liberal Democrats continue to talk, while others moot the idea of a 'progressive coalition' involving the SNP and Plaid Cymru, the pressure from the grassroots for a fair voting system and other reforms is likely to grow.