One in three children with a working single parent live in poverty, a new report warns, and this could rise dramatically by 2021.
The Gingerbread charity says young people in poverty are being excluded from the everyday activities and opportunities an average British child enjoys.
It estimates 1.7 million families are being let down by a lack of support from their workplaces and the Government, and warns almost two-thirds of children in single-parent families are likely to be living in poverty in just three years' time.
According to researchers, 68% of single mothers and fathers are now in work – a record high. More than half are classed as self-employed.
But Gingerbread says many of those who are self-employed often face volatility and low pay, and they are often forced down this route because jobs with decent pay and flexibility are "few and far between" for single parents.
Research suggests that there has been a tenfold rise of zero-hour contracts in the last ten years.
Gingerbread's chief executive, Rosie Ferguson, said: "Single parents are being let down at the moment – there's absolutely no reason why single parents and their children shouldn't be able to participate fully in the economy but they are twice as likely to be living in poverty as children in couple families.
"I think that's a result of the fact that our workforce is not friendly or accessible to people with families."
The Resolution Foundation, an independent think tank which aims to improve the standard of living of low and middle-income families, is concerned about the impact Universal Credit is having on single-parent families.
Senior policy analyst Conor D'Arcy said: "Single parents are more likely to be in receipt of tax credits and when they move on to Universal Credit, people who are not working and those who are will face cuts.
"Some of those cuts for families will be quite large, we're talking over a thousand pounds for some of those families.
"It's something where the Government could act and make a really positive difference for single parents."
A Government spokesperson said: "We recognise how challenging it can be for lone parents to juggle work and family life.
"That's why we've taken steps to double free childcare, and for the most in need paying up to 85% of their childcare costs under Universal Credit, to support parents back into work.
More from poverty
"Children living in households where someone works are less likely to be in poverty and more likely to do well in school, compared to those growing up in workless households.
"Our support is all about ensuring every child and family has the best chances in life."