A report on family breakdown suggests the instability of cohabiting couples has fuelled the disintegration of families in the UK.
Since 1996, the number of people cohabiting has doubled to nearly six million, the Centre for Social Justice (CSJ) found.
The report, Fractured Families: Why Stability Matters, stated that cohabiting parents are three times more likely to separate by the time a child is five years old than married couples.
It also highlights the cost of family breakdown, which the CSJ said is estimated at £46 billion a year or £1,541 for every taxpayer in the country.
This has risen by almost a quarter in the last four years and is projected to reach £49 billion by the end of this Parliament, the CSJ added.