By Alex Stevenson in Birmingham Follow @alex__stevenson
Liberal Democrats and other 'yes' campaign supporters are "owed" an explanation for their defeat in the electoral reform referendum, Chris Huhne has said.
Two-thirds of those who voted on whether to swap first-past-the-post for the alternative vote system rejected the idea, denying the Liberal Democrats an opportunity to improve their representation in Westminster.
Mr Huhne told a fringe event at the Lib Dem autumn conference in Birmingham that he was surprised by the referendum's result, given the huge public anger against the political world sparked by the expenses scandal.
"Arguably we should have been able to convert that into a movement which took us on to [winning] the AV referendum," the energy and climate change secretary said.
Mr Huhne said he had helped build up the £1 million war chest spent by the Electoral Reform Society (ERS) on the unsuccessful referendum campaign.
He warned that lessons from the failure needed to be learned quickly, as another referendum was a possibility after the next general election.
"The problem that we were attempting to solve was not always immediately apparent to voters," Mr Huhne said.
"I think we are owed a really thorough post-mortem on what went on. I'm trying to be as positive as I can about this, bearing in mind we may be fighting another referendum rather more quickly than we think.
"We need to know what went wrong so we do not make the same mistakes again. The best possible way of failing next time is to hush it all up, disregard it all and say 'it was something in the water supply'."
Mr Huhne demanded that a written analysis be produced of the failings which could be widely distributed.
An event giving campaigners an opportunity to assess the mistakes made will take place in November, former Yes To Fairer Votes campaign chief Katie Ghose said.
The ERS is also preparing a document to be placed in the hands of those responsible for the next campaign.
Shadow business secretary John Denham also spoke at the event. He attacked the "own goals" of the campaign, including its emphasis on backing AV as a way of forcing MPs to work harder.
That strategy was formed in the summer of 2010 before Labour became involved, politics.co.uk understands. Labour's initial exclusion nearly led to there not being a Labour Yes To AV campaign formed at all.
Mr Denham suggested that although the campaign could have been run better, it would never have been able to overcome the opposition from the 'no' camp.
"If we're honest with ourselves," he added, "on most doorsteps people said 'what's wrong with the current system?'"