DAVID Cameron has left the way open for the Conservatives to propose cutting the top rate of tax for high earners from 45p to 40p ahead of next year's General Election.

It follows London Mayor Boris Johnson call for the Prime Minister to "open up some more blue water" to Labour by cutting the top rate to just 40p for those earning more than £150,000 a year.

Shadow Chancellor Ed Balls on Saturday announced plans to restore the higher rate to 50p.

Ed Miliband three times challenged Mr Cameron at Prime Minister's Questions to reject the proposal and each time he refused to do so.

The Labour leader asked him who said before the last election: "Showing that we're all in this together means showing that the rich will pay their share, which is why the 50p tax rate will have to stay?'" Mr Miliband later confirmed it was Mr Cameron.

The Prime Minister pointed out how under the Coalition the richest would pay more in income tax in every year than in any year under the previous Labour administration. No 10 pointed out Britain's top 1% of high earners were paying almost a third of all income tax, compared with just over a quarter under the last Labour government.

"I want the richest to pay more in tax and under this government they are because we are creating jobs, we're creating growth, we're encouraging investment. And what we heard from Labour over the last 48 hours is they want to attack that growth, they want to attack those jobs, they want to attack those businesses. We now have in Britain an anti-business, anti-growth, anti-jobs party," Mr Cameron told MPs.

Mr Miliband stressed how Labour's 59p policy had the "overwhelming support of the most important people of all, the people of Britain" and again asked if the Tory leader was considering a proposal to cut the higher rate to 40p.

Mr Cameron stressed the Coalition's priority was to "cut taxes for the lowest paid and for middle-income people" and accused Labour of believing in "the politics of envy, not in raising money for public services".

Then Mr Miliband asked him to rule out another tax cut to the richest. The PM again stressed the priority was to cut taxes for the lowest paid.