Not everyone liked Ed Miliband's attempt to link the riots to the banking crash, the expenses scandal and the phone-hacking scandal. Boris Johnson, for instance, quipped in his Telegraph column today: "I simply cannot agree that Gerald Kaufman's expense-claim for a Bang and Olufsen television has somehow triggered or legitimated the torching of property in outer London."

But it's worth noting that both David Cameron and Iain Duncan Smith have since followed Miliband and made the connection. Appearing on the Today programme this morning, Duncan Smith remarked:

We all have to put our hands in the air, those of us in leadership positions, and recognise in the last 15 or 20 years what has happened to us is that many of us have just decided that life is about what you take out of it, not what you put in. You know, stiffing somebody on a debt in the City, or raiding someone's telephone for messages, claiming expenses that you should not have claimed - these are issues that all of us have to recognise we have to put our own house in order at the same time, and try and change that.

While Cameron used the closing passage of his speech (read the full transcript here) to make a similar point:

Moral decline and bad behaviour is not limited to a few of the poorest parts of our society. In the banking crisis, with MPs' expenses, in the phone hacking scandal, we have seen some of the worst cases of greed, irresponsibility and entitlement. The restoration of responsibility has to cut right across our society.

Both were echoing Miliband, who argued on the Today programme last Friday:

It is about irresponsibility wherever we find it in our society. We've seen in the past few years: MPs' expenses, what happened in the banks, what happened with phone hacking, what do those things share in common ... it's a lack of a sense of right and wrong, and a "me first" mentality.

As both parties fight to define the political reaction to the riots, the Labour leader can count that as a small victory. The challenge for the left is to now address the right's main explanation for the riots: family breakdown. Miliband made a good start in his speech this morning (read the full transcript here) when he argued that such a narrative was too simple. As he noted, "[T]here are single parents who do a brilliant job and two-parent families who do a terrible job." He added: "Some people say it's all about the feckless at the bottom, but there are rich families unable to control their kids and poor families who do it very well."

Cameron spoke today of a "family test" that would be applied to all domestic policy. If it hurts families and undermines commitment, he said, "then we shouldn't do it." But Cameron will struggle to make this argument while simultaneously rolling back state support for families. An unusual number of benefit cuts - the abolition of baby bonds, the three-year freeze in child benefit, the abolition of the health in maternity grant, the withdrawal of child tax credits from higher earners - hit families hardest. By contrast, benefits for the elderly - free bus passes, free TV licences, the winter fuel allowance - have been left entirely untouched. In addition, as I exclusively revealed in the NS last month, Cameron has broken his promise to protect Sure Start and 20 centres have already closed. So long as the PM's rhetoric is unsupported by his policies, this will prove fertile territory for Miliband.

Update: Cameron has now acceded to Miliband's demand for a commission of inquiry.