Some 15 million people are falling behind on bills and using credit to pay for essential costs, a debt charity warned this week.
StepChange said it is particularly true of those on low and average incomes, families with children, people aged between 25 and 39 and those renting privately.
The charity's research also suggested that millions of households' finances are so fragile that they are weeks away from falling into a spiral of debt.
The study showed that 13 million people do not have the savings to keep up with essentials for a month if their income were to drop by a quarter. StepChange's chief executive, Mike O'Connor, said: "Millions ... are living on the edge financially and are not prepared for the future.
"Unless we can improve families' financial resilience, it is likely that more people will be pushed over the edge, often as a result of resorting to high-cost credit."
The charity has called for a national strategy to help households avoid problem debt. "We need to act now," Mr O'Connor said.