The hope among the Tories is that the Libor scandal could yet prove more damaging for Labour than for them. But today's PMQs suggests they are likely to be disappointed. The endless argument between Ed Miliband and David Cameron over which party was more committed to "light-touch regulation" matters less than who is seen as toughest on the banks now. 

Today, Cameron's continuing refusal to establish a judge-led inquiry allowed the Labour leader to play the radical. The key moment came when he said of Cameron, "whenever a scandal breaks, he's slow to act and he stands up for the wrong people". One of the poll findings that most troubles Conservative strategists is the public perception that they are far too close to the banks. Yet Cameron has missed another opportunity to rebut this perception. Miliband's declaration that the Tories are a party "bank-rolled by the banks" will resonate with voters.

Cameron seemed oddly underprepared for Labour's attack, ending his exchange with Miliband with the weak quip: "we've found the Higgs Boson particle. But Labour haven't still found a sense of shame." He can continually remind the public that Labour was too close to the banks but this won't alter the perception that he's in the wrong place now. Cameron eventually resorted to the argument that Labour opposes a parliamentary inquiry because it doesn't want its "dirty washing aired in public". If so, why does it support a full judicial inquiry? There was no one left to ask him.

The other notable thing about today's PMQs was how subdued Ed Balls seemed, his heckles muted, his gestures weak. The Tories will hope and Labour will fear that he was preoccupied with his alleged role in the Libor scandal.