By Ian Dunt
Chris Huhne has issued an extraordinary attack on Tory chairman Baroness Warsi, as splits over the AV referendum threatened to divide the Cabinet.
The energy secretary accused the 'no' campaign of adopting the "politics of the gutter" through its continued reference to a £250 million cost claim that the 'yes' camp flatly denies.
'No' campaign posters have appeared claiming that the AV referendum is depriving babies of hospital equipment and soldiers of body armour.
"When David Cameron launched his 'no' campaign, he said this should not be a source of tension between us or risk breaking the coalition," Mr Huhne wrote.
"It won't, if your 'no' camp now withdraws these disgraceful advertisements and campaigns on facts not fears, substance not smears."
The 'no' camp says it arrived at the figure by adding the £150 million price of electronic machines to count votes, the £82 million cost of running the election and £20 million in publicity campaigns so voters understand the new system.
But the 'yes' camp point out that there are no plans to buy voting machines and that the other figures are just guess work.
Tomorrow sees a cross-party rally in favour of electoral reform, with Labour leader Ed Miliband standing beside former Lib Dem leader Charlie Kennedy and Caroline Lucas, leader of the Green party.
Mr Miliband refused to share a platform with deputy prime minister Nick Clegg. Many 'yes' campaigners believe the Lib Dem leader has become a liability in the campaign due to his unpopularity.
Speaking to the Financial Times today, Mr Clegg said the Labour leader had "elevated personal abuse into a sort of strategy".
Mr Miliband was prone to "slightly infantile" party political point-scoring, the deputy prime minister added.