For almost a decade now, what social conservatives say and the evidence in front of our eyes has been diverging with remarkable speed.

According to the received wisdom, the permissive revolution of the 1960s led to family breakdown, which in turn led to today’s terrifying crime rates. The small snag with the argument is that crime rates are not terrifying. The decline in marriage and rise in divorce notwithstanding, crime rates have collapsed.

Social conservatives can take some comfort from the fact that the fall coincides with the increase in the prison population since 1990. But a rise of about 30,000 in the number behind bars is small beer when set against, the vast and vastly welcome fall in crime.

The murder rate has seen the most startling decline of all. It has all but halved from 1,047 in 2002-03 (when the 172 victims of Dr Harold Shipman were included in the figures) to to 550 homicides in 2011-12 — the lowest level since 1983.

My old friend Alan Travis of the Guardian explains the decline by pointing out that two thirds of murders involve a (nearly always male) partner abusing his (nearly always female) partner or ex-partner. Crime has fallen because society’s attitudes to domestic violence have changed utterly. Since the 1990s, the police and the Crown Prosecution Service have taken domestic violence seriously. More to the point they were made to take it seriously by Harriet Harman, Vera Baird, Jacqui Smith and Labour’s other women ministers. I know they had a hard time in the Tory press — ‘crop-haired harridans’ and all the rest of it — but I admired their Cromwellian doggedness. Rather than follow the polls, they came to office with a clear determination to ensure that the criminal justice system treated women decently, and made damn sure that they got their way.

Other measures have helped drive down domestic violence. Rape crisis centres. Charitable and local authority efforts to get battered women away from their men and into emergency housing. Improvements in women’s education, and police campaigns that encouraged women to report and tackle abuse rather than treating them as ‘domestics’ to be kept in the family.

‘Keep it in the family!’ How resonant that phrase is when it has only been by interfering with the family that crime has fallen. Readers who want to uphold family values, should note that Cameron and Osborne are slashing police numbers, closing domestic violence centres and blocking off housing options for the poor. Perhaps the crime figures will soon reflect their success and show that in this instance at least the Tories have indeed taken us back to the ‘good old days’.

Tags: Conservatives, Crime, David Cameron, Family, family values, Harriet Harman, Tories