Electoral reform but not as you know it was the watchword as the Vote for a Change Rally launched a decidedly 'no anorak required' campaign to demand a referendum on changing the voting system by the time of the next General Election.
Dave Rowntree of Labour (and Blur) did squeeze in a few killer stats on the historic inequities of first-past-the-post before introducing KT Tunstall to sing. She said this had been a year of political re-engagement for her, revealing that her song 'Poison in your cup' had been "inspired by the look on George W Bush's face when Obama was inaugurated".
Making our discredited political class the face of the need for reform explained the focus on citizen and celeb-led approach, with campaigning poet Dave Neita also pitching in as a laureate of the left, as this fundamentally pro-politics cause seeks to surf an anti-politician wave.
Pro-reform politicians did get a turn and John Denham was warmly received. Rowntree mentioning his 2003 resignation over Iraq in introducing his potted biog certainly didn't do him any harm either.
Denham warned that the scale of public reaction to the expenses crisis spoke to a deep sense of disconnection from politics. He found anti-politics profoundly worrying because "a society which loses trust in politics, which loses faith in democracy, loses the ability to shape its future", said Denham.
"Changing the electoral system has long seemed to me to be central to changing the way that people think about politics", said Denham, because the electoral system was driving an ever narrower political contest targetted on small but decisive groups of marginal voters.
"A system that gives those key voters ten, fifteen or twenty times the power of other voters, is a real problem if parties then recognise and respond to that with ever greater sophistication, as we do".
"That is why we sound so much more the same that we know that we are in practice", said Denham.
Denham said the government had "done the narrow thing" to sort out Parliamentary expenses but recognised that "the agenda has to be much broader than that". Denham acknowledged different views in Cabinet on electoral reform - where he, Alan Johnson and Ben Bradshaw were long-standing advocates of change - but the whole government had committed to opening up the issue of electoral reform.
"That is not a guarantee of a change of the electoral system. But there is the chance of a change. That is the challenge your campaign is taking on. And it is why what happens outside Westminster will be crucial", he said.
"Only the main opposition party is totally, without discussion and without debate, resolutely opposed to any change. Across the rest of our politics, the openness to change is there".
Other speakers included LibDem Jo Swinson, Peter Tatchell for the Green party, Gerard Batten MEP from Ukip, Oona King and Billy Bragg, with Martin Bell, Shirley Williams and Clare Rayner among those offering video voxpops on the big screen
The campaign (which I am supporting) is pushing for an electoral reform referendum to be held not later than the day of the General Election. That would require legislation to be in place by the start of November this year.
You can support the campaign here.