Ed Balls, the shadow chancellor, says that Labour is considering a mansion tax on Britain’s biggest homes, a policy previously associated with the Liberal Democrats.
Mr Balls’s flirting with the idea of a wealth tax suggests the party is prepared to target the rich to help meet its social objectives.
His comments, in an interview with The Independent, will also be seen as an attempt to foment tensions among Liberal Democrats.
Mr Balls said he would be happy to discuss details of the mansion tax with its chief advocate, Vince Cable, the Lib Dem business secretary, who comes from the left of his party.
With the Conservatives unwilling to implement the mansion tax, Mr Balls’ move will be seen as a signal to Lib Dems and their supporters that Labour is a more natural ally.
Labour officials insisted that wealth taxes, including a mansion tax, were not party policy but were being considered as part of a wider economic review.
Meanwhile, Ed Miliband, Labour leader, will on Thursday herald a shift in the party’s approach to tackling poverty, saying the state would in future not have the money to directly raise living standards.
Mr Miliband will say Labour’s old preference for helping the poor by using the fruits of an economic boom to pay for tax credits was no longer an option, acknowledging that Britain’s deficit would still need to be reduced after the 2015 election.
Instead he argues the party will have to come up with new policies to “make work itself pay”, by raising the skills of the workforce and possibly encouraging employers to pay a so-called “living wage”.
Mr Miliband’s team say that no decisions had been taken on the living wage proposal and there would no compulsion on employers to pay staff more, but some Labour local councils have adopted it in areas where living costs cannot be met by the legal minimum wage of just over £6 an hour.
The Labour leader wants to focus on the creation of “decent paid jobs”, although the Conservatives will argue that Mr Miliband’s party had 13 years in power to raise the skills and training of the workforce.
Business will also be anxious that Labour does not intend to impose costly new burdens on it, especially as the economy may still be in a fragile state in the aftermath of the 2015 election.
Those scouring Mr Miliband’s words for clues will find little comfort in his use of the expression “predistribution” – his description of Labour’s search for means to make work pay.
“The redistribution of the last Labour government relied on revenue which the next Labour government will not enjoy,” he will say. “The option of simply increasing tax credits in the way we did before will not be open to us.”
Mr Miliband and Mr Balls will set out the framework for their economic plans at the London Stock Exchange, although Labour remains wary of setting out specific policies more than two years from an expected election.
However, the Labour leader promises that new policies were being worked up. He will say that the party cannot wait for the government to fail “so that we can go back to governing as we did before”.
The Labour leader will identify three main economic challenges: the lack of demand, the need to “make work pay” as an alternative to traditional Labour redistribution, and building a “more responsible capitalism”.
Mr Balls, who favours an immediate demand stimulus through a temporary value added tax cut and a tax on bankers’ bonuses, will claim that “austerity has clearly failed in Britain” and will argue that Labour has won the intellectual argument.
Tensions have been reported over the summer between “the two Eds”, so their appearance on a joint platform at the start of the political season will be a chance for them to exude some fraternal bonhomie.
Mr Balls denied the reports as “total garbage”.
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