In addition, around 4.7 million have stated they do not have home insurance, while over a million people have driven a car without insurance in the past year.
Commenting on the study, the head of insurance at Sainsbury's Finance, Steve Johnson, said: "Insurance is an absolute must, but our research suggests that millions of people are playing Russian roulette by opting to do without.
"Those people finding it difficult to afford insurance due to the rising cost in living need to ensure that they shop around for the best cover because this can dramatically reduce price."
Sainsbury's Bank offers consumers a range of financial products, including insurance, loans, credit cards and savings accounts.
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