Miliband admits scrapping 10p rate of tax was a 'mistake'

Ed Miliband and his shadow chancellor Ed Balls couldn't have been clearer. It was a mistake - according to the Labour leader a very, very bad mistake - to scrap the 10p rate of tax.

Of course it was a decision made when both Eds were in Cabinet serving under Gordon Brown, even if Mr Balls says they made objections at the time. So it appears to be a big deal that they want to re-introduce the tax.

But there's politics at play here.

Firstly, there are Tory backbenchers, like Robert Halfon, who have been calling for the rate to be re-introduced. The MP even asked David Cameron about it yesterday at Prime Minister's Questions. And Mr Cameron certainly didn't dismiss the idea. But it looks like the Eds got there first.

Read: 'A remarkable failure to learn from history', analysis from Economics Editor Richard Edgar

Secondly, on Valentine's Day, Labour has made a pretty brazen attempt to woo the Lib Dems with talk of a mansion tax on homes worth more than £2 million to pay for the 10p pledge.

The party's delighted at that, with Business Secretary Vince Cable saying "it's good that they've seen sense".

But the Lib Dems are concerned that the 10p pledge will detract from their flagship policy of raising the personal tax allowance - the amount you can earn before you have to pay tax.

The Coalition's pledged to increase the threshold to £10,000 by the end of the Parliament. The Lib Dems want to increase it further in the next.

The Treasury is adamant Labour's plan won't help people because the rise in the personal tax allowance has already filled the void.

They are clearly furious at Labour's U-turn with even the Prime Minster claiming it hadn't been properly costed.

Economic Secretary, Sajid Javid, though, refused to rule out the move completely - the Tories have to keep their options open.

Labour is vague about how the mansion tax will work in practice and about how much it will raise. The party can't even promise it, along with the 10p tax pledge, will definitely be in their manifesto in two years' time.

But like the Lib Dems, they are trying to position themselves as the party of fairness. Even if it was Labour who scrapped the 10p tax in the first place.