Nearly three quarters of a million children and pensioners in the UK have fallen into relative poverty over the past four years, research suggests.
The Joseph Rowntree Foundation said it was the first sustained rise since 1997 of child and pensioner households with less than 60% of median income.
The charity said the “worrying” figures suggests progress in tackling hardship is in “peril”.
Ministers say their support is helping pensioners and families out of poverty.
According to the JRF report, since 2013 an extra 300,000 pensioners and 400,000 children are now living in poverty and the “prospects for solving” the problem “currently look worrying”.
Despite the government protecting the value of the basic state pension since 2010, the foundation says Pension Credit, a benefit paid to the poorest pensioners, has not kept pace with rising costs.
Researchers say the rise in child poverty has been driven by stagnant wages for low income families and a freeze on benefits and changes to tax credits, which many families, both in and out of work, rely on.
The charity says ending the benefit freeze is the single biggest change the government could do to help the 14m people – 4m children and 1.9m pensioners – now living in poverty.
New threats to the poorest households, including rising housing costs, higher food and energy bills, debts and not being able to contribute to a pension, said the foundation.
Campbell Robb, chief executive of the JRF, said: “These worrying figures suggest that we are at a turning point in our fight against poverty.
“Political choices, wage stagnation and economic uncertainty mean that hundreds of thousands more people are now struggling to make ends meet. This is a very real warning sign that our hard-fought progress is in peril.”
Shadow work and pensions secretary Debbie Abrahams said the figures were “totally unacceptable” and “a truly terrifying prospect for millions trying to make ends meet”.
A government spokesman said since 2010, the number of people in absolute poverty – an assessment of basic living needs which takes into account a household’s access to services as well as income – had fallen by more than 500,000.
He said: “We are spending an extra £4.2bn on pensioners, carers and disabled people next year, and continue to spend around £90bn a year supporting people of working age, including those who are out of work or on a low income.”
He added: “Pensioner poverty remains close to historically low levels and we are supporting parents with the cost of bringing up children by doubling free childcare.”