Joseph Rowntree Foundation found one million children under the age of four were growing up in poverty.
Campaigners have warned a lack of generosity in the benefit system means it is “fundamentally not fit for purpose” as they revealed millions of families are trapped in poverty.
A Joseph Rowntree Foundation (JRF) analysis found 13.4 million people were in poverty during the first year of the pandemic, including 3.9 million children.
But it argues the government is not “helpless” from preventing households falling into impoverishment, pointing to the £20-a-week Universal Credit uplift that reduced poverty among larger families and young children.
The temporary boost to social security was scrapped in October 2021.
The JRF said the withdrawal of the uplift coincided with spiralling inflation and the cost-of-living crisis, which has led to millions now going without basics.
According to JRF research this winter, around 7.2 million people are forgoing meals, showers and heating, and 4.7 million are getting behind on their bills.
Peter Matejic, chief analyst at the Joseph Rowntree Foundation said: “This winter we have seen two crises collide – the cost of living is forcing families to cut back on essentials and our health service is being overwhelmed by demand.
“Leaving people to go hungry, skip showers or live in cold homes risks further profound and long term consequences – not just for individuals’ health but for the state’s capacity to deliver what all of us as citizens should be able to expect.”
He added: “Governments are far from helpless and none of this is inevitable. The £20 uplift was the right political choice which clearly made a huge difference during the pandemic and may have prevented what were tremendously difficult years becoming a complete disaster for families around the UK.
“The relief provided by this measure, taken away just as the cost of living crisis hit, also demonstrated that the standard rates of social security are fundamentally not fit for purpose, with millions now going without essentials such as food, heating and cleanliness.”
He added it takes “political will and imagination to tackle multiple injustices at once”.
The report also found one million children under the age of four were growing up in poverty, even with additional support.
One in six (18%) children were living in persistent poverty, which is defined as at least three out of the last four years. Almost 40% of children in a lone parent family are in poverty, it added.
The JRF said the pandemic also highlighted huge health inequalities, with a strong overlap between poverty rates and where families live, their ethnicity and their health outcomes.
Jonathan Ashworth, Labour’s shadow work and pensions secretary, said: “The scale of the cost of living crisis and its impact on children across the country is devastating.
“Families have struggled through 12 years of Conservative mismanagement of the economy. This shows just how far families are now being plunged into hardship because they crashed the economy.
“Labour would be taking action right bring energy bills down and get living standards up and tackle the growing poverty crisis facing the country.”
A government spokesperson said: “We recognise that families across the country are facing financial pressures as a result of Putin’s war in Ukraine and the aftershock of Covid; that’s why we are committed to halving inflation this year to ease the cost of living.
“We have also intervened with a £26 billion support package which includes up to £1,350 of direct payments to the most vulnerable families next financial year, an increase on 2022’s direct payments. This is on top of our energy price guarantee, worth £900 to an average household this winter, and our energy rebate, which runs through until March and is providing £400 towards energy bills.
“We are also spending £1.5 billion on further support, with England’s household support und directly helping those in need with essential costs, and are currently offering free school meals to all five-to-seven year olds, benefitting millions of children in need.”