Huhne tells Cameron: stop vote reform 'lies' or you'll split the Coalition

Environment Secretary warns Prime Minister there will be 'a lot of bad feeling' in Government if referendum fight isn't fair

A Liberal democrat Cabinet minister has warned David Cameron that the "outrageous" Conservative-led No campaign ahead of next month's referendum on the voting system risks inflicting permanent damage on the Coalition.

Chris Huhne, the Energy and Climate Change Secretary, told The Independent that the Prime Minister should intervene to stop the No camp telling "downright lies". He cited its claims that a switch to the alternative vote (AV) would require electronic counting machines and cost £250m that could be spent on vital public services.

"There is no truth whatever in these outrageous allegations," he said. "It is absolutely astonishing that it could come from our Coalition partners. I fear it could damage the Coalition and diminish the respect his Coalition partners have for him [Mr Cameron]. There is no doubt that if you behave in a thoroughly reprehensible and underhand manner you are going to lose the respect of people."

Asked whether the increasingly bitter referendum campaign could shorten the planned five-year life of the Coalition, Mr Huhne replied that he could not make predictions about the future and that the two parties still "have a job of work to do".

But he warned that there would be "a lot of bad feeling" after the 5 May referendum unless there was a "fair fight", saying the two Coalition parties should observe a political equivalent of boxing's Queensberry rules. He accused the No camp of resorting to "out of order" behaviour that went "way beyond the normal cut and thrust of a general election campaign. I cannot remember a campaign where one side resorted to such underhand tactics."

Mr Huhne rejected Mr Cameron's claim that he was responsible for the Conservative No campaign but not the wider No campaign. Describing the latter as a "Conservative front organisation", he said "all the moving parts" – such as the funding and the people running it – came from the Tories.

"The only way you can explain why the Conservatives are acting in this way is desperation. They are clearly very worried about losing the vote," said Mr Huhne. "It seems the Conservatives are prepared to say virtually anything to try to win it." He said the Tories had enjoyed power for about two-thirds of the 20th century under first-past-the-post, even though they had won more than 50 per cent of the votes on only two occasions and did not want to see that dominance threatened in the 21st century.

As tensions between the Tories and Liberal Democrats over AV reached a new high, Lord (Paddy) Ashdown urged Mr Cameron to call off the No camp's personal attacks on Nick Clegg, who has featured heavily in its propaganda. The former Liberal Democrat leader told the BBC the No campaign had become "appallingly personal" and "no British prime minister" should be linked to it. He was "very, very angry" about the "Conservative Party money and the dinosaurs of Labour who are attacking the man holding the Coalition together".

He added: "This has become a deeply and appallingly personal campaign. It's centred on one personality and that is Nick Clegg. If he [Mr Cameron] wants to take a high-profile lead in this campaign, let him do so on the basis it is conducted with honesty and decency."

Urging Mr Cameron to intervene, Lord Ashdown said his continuing backing for the No campaign's tactics would inevitably damage "personal relations" within the Government.

Downing Street insisted that Mr Cameron is concentrating on the arguments against AV. A spokesman said: "The Conservative Party is running its own No to AV campaign. This is focused on highlighting how unfair and unpopular the AV system is and why people should vote No. It is a system that is obscure, unfair and expensive and could mean that people who come third in elections end up winning. It is not attacking Nick Clegg."

Jane Kennedy, a former Labour MP who is national director of the No to AV campaign, called Lord Ashdown's attack on the No camp an "astonishing outburst" and claimed that the Liberal Democrats had "perfected the technique" of conducting personally abusive campaigns. She claimed that it was the fact that Mr Clegg had "traded away his pledge" on tuition fees that was turning people "away from the case for change".

Clegg forgoes £38,000 profit

Nick Clegg has set an example to MPs still profiting from the old rules on expenses. He sold his Sheffield home for £325,000 and gave the £38,750 profit to the taxpayer, although he did not need to. Mr Clegg lives in London but rents a home in Sheffield. A rule allowing MPs claim for mortgage payments on second homes has been scrapped.