The Prime Minister made Father's Day headlines with a scathing attack on "runaway dads" who, he said, should be "stigmatised" in the same way as drunk drivers. Such fathers, he said, needed the message "rammed home" to them, that "leaving single mothers ... to fend for themselves simply isn't acceptable". The only trouble with building up such a head of steam about paternal responsibility is that very few people would probably disagree.

In appearing to lump all absent fathers together as reprobates, however, David Cameron is making the same mistake as those who habitually brand single mothers feckless. While judges have become more open-minded in custody cases, the bias is usually still towards mothers in disputes. And while many agreements on access operate flawlessly, many do not, with otherwise responsible fathers losing hope that court orders will ever be enforced. In such circumstances, it is understandable – if wrong – that they may become less enthusiastic about maintaining contact and paying child support. Add the still imperfect workings of the Child Support Agency, and irresponsibility is not always on the father's side.

Tax and benefits also leave something to be desired. A system, such as we have now, which can make unemployed and low-paid people substantially better off if they are single with a child than if they live together as a family is little short of a recipe for absent fatherhood. In his article, Mr Cameron said his government was tackling the so-called "couple penalty", and he again raised the possibility of recognising marriage in the tax system. But it is not necessary to go as far as rewarding marriage financially to eradicate the perverse incentives that currently exist for parents to live separately.

While any government has limited power to change personal behaviour – and "runaway dads", as "feckless mums", will always be with us – Mr Cameron sometimes sounds as though he is still in Opposition. If more fathers are to take responsibility for their children, the social stigma he advocates could do with being tempered by encouragement.