The political hot potato that is bankers' bonuses was lobbed back into Coalition hands yesterday as Labour duo Ed Miliband and Alan Johnson criticised the Government for failing to renew the tax on bonuses.

The Leader of the Opposition and Shadow Chancellor claimed that the policy replacing the bonus tax, the levy on banks' balance sheets, equated to a “tax cut” for the financial services sector. Yet there was some confusion over the exact amount by which banks were benefiting from the change.

Alan Johnson was quoted in yesterday's Mirror as saying: “The money that is being taken off the banks is about £2.6 billion. That is less than the money coming off children through child benefit, less than the money coming off students through the cuts in higher education. That is not a proportionate contribution to bringing down the deficit.”

However speaking at a press conference yesterday, Ed Miliband claimed that the figure being raised through the Coalition's bank levy was £1.25 billion.

It is this latter figure that corresponds more closely with the Treasury's own projections. In June's Budget, the permanent bank levy was projected to raise £1.15 billion in the forthcoming 2011/2012 financial year. This estimate was subsequently upgraded to £1.3 billion in its first year of operation by HM Revenues and Customs (HMRC).

However looking at the longer term forecasts in the Budget, the figures rise to around the level suggested by Alan Johnson in the Mirror, as the rate is raised from 0.05 per cent of balance sheets in 2011/2012 to 0.075 per cent from 2012/2013. According to HMRC the revenue from this higher rate peaks in 2013/14 and 2014/15, where £2.6 billion is forecast to be raised annually.

Both the £1.25 billion and £2.6 billion figures could be seen as accurate therefore. It is understandable why Mr Miliband should choose the lower figure in the circumstances, however it certainly doesn't aid clarity when the same party uses different figures to quantify the same measure in the space of a single day.