It does not require a hidden microphone in David Cameron's Downing Street flat to know that he must be finding the Labour leader increasingly irritating.

Ed Miliband snatched the political steering wheel from the Prime Minister four months ago with his bold announcement of plans for an energy price freeze, setting the direction of travel for weeks afterwards as the Government scrambled to regain control in the face of energy price hikes.

Now the Labour leader has come up with another ruse to embarrass the Tories, calling on the Government as RBS's majority shareholder to refuse bonuses of more than 100% of salary, in line with incoming EU rules. Would Labour be so tough in government? Mr Miliband might find it harder than he makes out, but unfortunately for Mr Cameron, that is not the point. The Conservatives have struggled to shake off the "party of privilege" tag. Voters suspect that they lack the will to tackle the high rolling culture of excessive bankers' bonuses, and Mr Cameron's rather anaemic response to Ed Miliband yesterday did nothing to dispel that notion.

The Prime Minister refused to rule out share-based bonuses of more than 100%, trying to garner credit instead for saying the Government was capping cash bonuses at £2000 (though that is already the case) and that it would veto any overall increase on the bill for salaries and bonuses. The Government has pointed to a drop of £1.6bn in the pay bill at RBS since 2010 as proof of its willingness to get tough on bonuses, but as Labour points out, the bank has shed 40,000 staff including 2000 investment bankers in that time, so the statistics say nothing about each individual's pay. In fact, some executives were paid more than 100% of their pay as a bonus last year. Another 2000 jobs going in RBS's investment wing, which makes it very easy indeed for Mr Cameron to talk of holding down overall pay costs.

There is little doubt that the excessive pay and bonuses of investment bankers not only encouraged the high risk activity that led to the banking crash but is out of kilter with most other professions and is therefore widely regarded as a culture of greed. By being asked to accept a bonus capped at 100% of salary, bankers are not being denied the fruits of their labours; they are merely being asked to take a huge bonus instead of an enormous one.

The difficulty for Labour, however, is that the EU's cap on bonuses does not have the backing of the Bank of England or the cross party Parliamentary Commission on Banking, since it is viewed as ineffectual. Banks are expected to try and get around the cap by simply offering bigger salaries instead. The Chancellor has warned this would make it harder to recover the money if something went wrong with a bank.

That is a risk, but no-one will ever know if the size of bonuses is never challenged. How likely, truly, is RBS to suffer from a cap on bonuses of 100%? Even thus restricted it would be able to offer rewards that are a world away from the pay freezes and below inflation increases endured by the taxpayers that own the bank. It is a risk worth taking.