SKY NEWS

A Liberal Democrat minister has accused his Cabinet colleague of "poisoning" politics as a public row over the voting reform referendum worsens and descends into personal attacks.

Energy Secretary Chris Huhne has written to Baroness Warsi, the Conservative party co-chairman and minister without portfolio, calling on her to stop spreading "scares and smears" about supporters of the alternative vote (AV).

The letter, which breaks traditional Cabinet etiquette, is the latest development in a spat that has already included mentions of Nazi propaganda, reports Sky News.

Huhne is a prominent advocate of AV along with Deputy Prime Minister Nick Clegg and other Liberal Democrats.

But Tory Baroness Warsi wants the electorate to vote 'No' on May 5 and argues the alternative system would allow more extreme parties, such as the British National Party (BNP), to get elected.

That claim prompted the Energy Secretary to publicly describe her campaign as "increasingly Goebbels-like" - a reference to Nazi leader Adolf Hitler's propaganda minister.

Now Huhne has written to the Tory peer to ask: "Are the No camp campaigning in dark glasses because they don't want to show that the bulk of their funds, in cash and in kind, are donations from the Conservative party?"

According to The Observer, he went on: "How many Conservative employees have been seconded to the No campaign?

"Will you declare the full value of their services properly as donations?"

He called on Baroness Warsi to stop using "secret donations to advance scares and smears" and added, "Please stop now before you poison our politics".

The Yes campaign says 95% of its funds come from the Electoral Reform Society and the Joseph Rowntree Trust.

'No' campaigners have yet to declare their donors but say they plan to do so. It is within the rules to keep the details secret for another six months.

A spokesman for the No camp told the paper: "Would Chris Huhne like to tell us if he believes there is a conflict of interest in the largest donor to the Yes to AV campaign, the Electoral Reform Society, running elections in London and in Scotland providing the electronic vote-counting machine and using public money to do so?"

The governing parties are on different sides of the voting reform debate with the Lib Dems putting calls for a more proportional system at the heart of their General Election campaign.

In contrast, Conservatives including Prime Minister David Cameron want the existing system to stay.

A referendum on the issue was a key plank of the coalition agreement signed by the two parties.

Opposition leader Ed Miliband supports the Yes To AV campaign but many of his Labour MPs take the opposite view.

In contrast to the diplomacy they normally display when they disagree, the Prime Minister and Deputy Prime Minister have both delivered thinly-veiled attacks on the other's position.

On Friday, Cameron called Alternative Vote "crazy" and said "they" - the 'Yes' camp - used to consider AV a "miserable little compromise", a phrase once used by Clegg.

Under the current system of first-past-the-post, voters put a cross next to one candidate's name and the person with the most votes wins the seat.

But under AV, voters would rank the candidates in order of preference.

If no candidate gets 50% of the vote on the first round, the least popular candidate is eliminated and their "second preferences" are redistributed among the remaining candidates.