"Our advice is that the carbon tax in its current form is unconstitutional" ... Clive Palmer. Credit:Glenn Hunt Last night, Mr Palmer hit back, saying: ''I've given away each year more than a hundred times the Treasurer's salary to Australians who are needy. I wonder how much of his salary has he given away to Australians who need that wealth.'' Mr Palmer denied that launching a High Court challenge would prove Mr Swan's accusation that he and other mining bosses were using their wealth to distort public debate. ''We've all got the right to go to High Court,'' he said. The 57-year-old Queensland magnate, who has an estimated $5 billion fortune from iron ore, nickel, coal, oil and gas, threatened in November to launch a Federal Court challenge to an anticipated $30 million carbon tax bill. Last night he told the ABC: ''You can't really tax carbon. The other thing about it, of course, is it's a joke. Of course the air moves right around the world. If you tax something in Australia, those emissions will go offshore, those jobs will go offshore.''

Mr Palmer's threat on carbon tax caps a busy time in the public eye. Yesterday it was reported he was looking at investing in media groups such as Fairfax, owner of The Age, in partnership with other wealthy Australians and running them through a ''blind trust'' arrangement. Last week he vowed to sue Football Federation Australia unless he was given back his licence for Gold Coast United in soccer's A-League. Mr Palmer has also been a prominent campaigner against the mining tax, which yesterday remained mired in controversy as Opposition Leader Tony Abbott dug in against the related proposal for a cut in company tax, despite calls from business to pass it. Mr Abbott has also refused to recommit to the 1.5 per cent company tax cut promise that he took to the last election, saying he would give a ''modest'' cut. The Business Council of Australia said if implementation of the mining tax was inevitable, passing the company tax cut was ''essential for the strength of the Australian economy''.

Heather Ridout, head of the Australian Industry Group, said a cut in company tax was needed to make the economy more competitive - although the proposed reduction from 30¢ to 29¢ did not go nearly far enough. Prime Minister Julia Gillard seized on the Coalition's vow to oppose the company tax cut - which is funded from the mining tax that it has promised to repeal. Ms Gillard said: ''I never thought I would see the day that the Liberal Party would join with the Greens to vote against a tax cut for business.'' But Mr Abbott said the tax cut was a con because it was paid for by a tax increase. The Greens say they will pass the tax cut for small business, defined as those with an annual turnover of up to $2 million, but will oppose the cut for bigger businesses. Small businesses are due to get the cut from July and bigger businesses a year later. The BCA and the Australian Industry Group both attacked the Greens' plan to approve the cut only for small business. ''Businesses of different sizes are deeply interdependent,'' BCA boss Jennifer Westacott said.

The Baillieu government would not comment on Mr Abbott's vow to block the tax cuts, a move that could potentially deny Victorian businesses about $600 million in relief. ''It's a matter for the federal Coalition to consider the detail of Labor's bill, and the detail of any amendments proposed by the minor parties,'' a spokeswoman said. With the Victorian economy under pressure from the high dollar, the mining boom and global uncertainty, state business groups have ramped up demands for tax relief. Australian Industry Group Victorian director Tim Piper said businesses were particularly concerned about payroll taxes and WorkCover premiums. But he said an across-the-board company tax cut would be a sensible option in the current climate. With JOSH GORDON