More than 10 million households are feeling financially squeezed and almost one in 10 have defaulted on a loan, bill or housing costs, a consumer group says.
Releasing its findings ahead of Chancellor George Osborne's Autumn Statement this week, Which? urged the Government to ensure spiralling energy and food costs are kept under control.
The group's "squeezometer" found almost one in four people (39%) are feeling financially squeezed, equating to 10.2 million households.
Researchers found 9% of households have defaulted on a loan, bill or housing costs, equating to 2.3 million families if the figures are projected nationally.
Some 6% of households have gone into an unauthorised overdraft or used a payday loan to tide themselves over, which would be around 1.5 million families on a national level.
Researchers highlighted consumers' top worries as the price of fuel, energy and food.
A string of energy firms have recently announced bill hikes, putting further pressure on families this winter.
Food costs are also on the increase, and last week the Office of Fair Trading (OFT) said eight supermarkets have agreed to a set of principles following concerns over special offers and promotions for food and drink.
The supermarkets have agreed not to artificially inflate prices to make a later "discount" look more attractive.
Which? executive director Richard Lloyd said: "With 10 million households feeling the squeeze and consumer confidence remaining low, the Government has a job on its hands to convince people that everything possible is being done to keep unavoidable costs like energy and food bills under control."