NICK Clegg will today insist the Coalition policy of raising income-tax-free allowances js "twice as good" in helping working families as Labour's plan to resurrect the old 10p income tax rate.
The Deputy Prime Minister will brush aside Ed Miliband's call for a mansion tax, describing it as "blatant plagiarism" during a speech in the City.
His rebuff to Labour comes after Vince Cable knocked back suggestions, from within the Liberal Democrats' own ranks, for a new French-style tax on jewellery, paintings and other expensive assets, dismissing them as "wacky".
The LibDem Business Secretary also poured cold water on suggestions, again from within his own party, that their controversial proposal for a 1% annual levy on mansions worth more than £2 million could be extended to cover all property assets, including second homes and buy-to-lets.
The ideas have been produced by a party panel ahead of the LibDems' spring conference in Brighton next month for possible inclusion in the 2015 General Election manifesto.
The internal policy consultation concluded there "may be merit" in imposing the 1% levy not on mansions alone but on anyone with a land and property portfolio worth more than the £2m threshold.
It also mooted a wider French-style wealth tax on asset that would involve tax inspectors visiting people's homes to verify the value of declared items.
However, Mr Cable gave the suggestions short shrift, saying: "Some of their ideas are interesting; some of them are a bit wacky."
He added: "The idea of taxing jewellery is completely impractical and intrusive. The idea that you combine together people's properties probably doesn't make a great deal of sense because people's second homes are already subject to capital gains tax and income tax on the rent."
The Secretary of State made clear many of the ideas would not go any further, but stressed the LibDems as a party had "activists who come forward with ideas, we debate them and then we make policy".
"But we are a long, long way from that and these ideas are most emphatically not party policy," he said.
Before the March 20 Budget, Labour is planning to use an Opposition Day debate in the Commons to force a vote on the mansion tax, which it now supports to help pay for a new 10p income tax rate.
Mr Miliband has challenged Mr Clegg and his LibDem colleagues to support the Labour motion. However, senior party sources have suggested this is a clear political stunt by the Labour leader to try to split the Coalition and use the Deputy Prime Minister to embarrass David Cameron.
Mr Cable welcomed Mr Miliband for "seeing sense" and supporting the LibDem mansion tax, saying the policy's time had come, but warned the Labour leader against playing political games and said if the vote was linked to the 10p tax rate, his colleagues would not support it.
Meanwhile, Conservative Party chairman Grant Shapps said raising thresholds was the most efficient" way to ease the tax burden, and hinted the Tories would look at pushing it beyond the £10,000 target for this parliament.
Asked about the prospects of the Chancellor adopting the 10p rate, he said: "What I will say is I'm absolutely confident that we will reduce tax, not to 10% but to zero for even more people by the election."