Research by VoucherCodesPro.co.uk found people who let their car and home insurance policies roll over automatically rather than shopping around spend an average of £339 more than necessary for coverage.

Car insurance companies are most likely to automatically increase prices at renewal, the study said.

Some 78 per cent of people said they had agreed to the their existing car and home insurers quotes at renewal with no further investigation, while only 22 per cent shopped around.

The majority of people said they had forgotten their insurance was about to expire, missing the window of opportunity to shop around, while 12 per cent said they ‘never got around’ to comparing prices.

Only 19 per cent stuck with their current insurer because they were happy with the price quoted.

The average savings for those who did compare other insurance options was £283 for a car insurance policy. Those comparing home or contents insurance saved £56 on average.

George Charles, spokesperson for VoucherCodesPro.co.uk, said: “Consumers must be vigilant when it comes to insurance renewals, because it’s down to them to make sure they compare prices and find the best deal possible.”