One in three families now has the mother as the main breadwinner, a new study reveals.
The research uncovers a new socioeconomic phenomenon with major implications for government policies on childcare and shared parental leave.
The number of breadwinning mothers, which includes those earning more than their partner or those who are working single mothers, has soared from 18 percent 15 years ago to 31 percent today, the study by the IPPR think tank found.
More than 2.2 million working mothers are the main earners in their families, an increase of one million, or 83 percent, since 1997, the Independent reported.
When child benefit and other measures are taken into account, working mothers contribute more than half of all earnings to family budgets.
The rise has been driven by a steady increase in women's opportunities in the workplace, coupled with a steady decline in traditionally male jobs in manufacturing.
Economic austerity has also driven single mothers who previously did not work to look for employment, researchers said.
The number of cohabiting mothers who are breadwinners has doubled since 1997 to 200,000, a faster rate than married parents and single working mothers.
However, the employment rate of single mothers has increased from 43 percent in 1997 to 58 per cent last year, the latest figures found.
Graduate mothers are more likely to be breadwinners than those with fewer skills, with 35 percent of mums with a degree earning more than their partner, compared with just over a quarter for those without this level of qualification.