Conservative leader David Cameron has pledged to put families at the heart of his agenda, as a party commission warned that marriage breakdown was behind many of Britain's social problems.
A study led by the Tories' former leader Iain Duncan Smith warned that massive debt and broken families were creating a "growing underclass" in the UK and called for a radical reappraisal of policy on marriage.
Hailing the report as "powerful and convincing", Mr Cameron said that Tory policies should aim to help families stay together - possibly by reforming the tax system to reward marriage.
"If marriage rates went up, if divorce rates came down, if more couples stayed together for longer, would our society by better off? My answer is yes," he said.
"And so I will set a simple test for each and every one of our policies: does it help families?"
Launching the Conservative Social Justice Policy Group's interim report on Breakdown Britain, Mr Duncan Smith said that family breakdown cost the UK more than £20 billion a year and was driving a violent crime wave that was tearing communities apart.
Family breakdown, educational failure, economic dependence, indebtedness and addictions were "all inter-related", he said.
"Children from a broken home are twice as likely to have behavioural problems, perform worse at school, become sexually active at a younger age, suffer depression and turn to drugs, smoking and heavy drinking," said Mr Duncan Smith.
"The increasingly dysfunctional society described in this report is one that breeds criminality."
He made clear his belief that marriage was the key to stable families. Nearly half of cohabiting couples had broken up by the time their first child was five, whereas the figure for married couples was much lower, he said.
