Ed Miliband's Clause IV moment

Along with everyone else who follows the Westminster soap opera, I've been deeply unconvinced over the last nine months by Labour's new leading man. Ed Miliband was - to be generous - only the third best candidate in the leadership election last year, and he's been going downhill ever since he won.

For far too much of the time he's looked solemn beyond his years, akin to the 12-year-old Jesus discussing theology with the elders in the Temple: 'all that heard him were astonished at his understanding and answers'. Except that what would have been considered precocious wisdom in a schoolboy looks like immaturity in a man in his forties.

But the News of the World story this week has caused him to up his game considerably. He was impressive at prime minister's questions and he's kept the pressure on David Cameron for the last couple of days.

And yet I can't help feeling that he's not making full use of the opportunity. Cameron's press conference this morning showed again what a competent operator he is. Miliband can damage him with the Andy Coulson and Rebekah Brooks connexions, but at this stage of the parliament, such wounds aren't going to be fatal. And possibly they're not going to be very long lasting.

Miliband should really go beyond simple attack mode and seize the moment to make a decisive break with the excesses of New Labour's past. During Tony Blair's period in office the press, politicians and financial institutions displayed a contempt for morality, and even legality, as they reached new levels of arrogant, irresponsible behaviour that have brought all into disrepute and sent some to jail. The gap between rulers and ruled became uncomfortably and dangerously wide, and , while the Labour government may not have caused all the problems, it certainly did nothing to solve them, and its negligence (at best) made them worse.

Of course Miliband was involved in that government. But only in a junior capacity. He's young enough that he can present himself as a fresh start, but to do so he has to wash his hands publicly of the past. Just as Blair jettisoned Labour history with the rewrite of Clause IV, so Miliband can now shed the embarrassing and unpopular parts of New Labour history. One of the things that most irritated the electorate about Blair was his refusal to apologise - there would be something rather refreshing if Miliband were now to say sorry for the things that went wrong.

Above all, he'd look much more secure on the moral high ground if he could present himself as a repentant sinner.