Car insurance customers are being hit with "eye-watering" administration fees, an investigation by the consumer watchdog Which? has found.
Which? is running a "stop sneaky fees and charges" campaign.
The watchdog found that the admin fees used by car insurers can vary widely, with some charging double the average for certain costs.
Of the 44 insurers Which? looked at between May and August, it found that five did not have any adjustment fees for changing details such as a name or address, while others charged up to £35.
The average fee for this was £22.79, Which? found.
Two-thirds of insurers charged for cancelling during the 14-day cooling-off period, with the cost being as high as £75.
Previous Which? research found that two-thirds, or 68%, of consumers thought companies used separate fees to trick people into thinking the product or service was cheaper than it was.
Which? is urging companies to set out all fees and charges clearly so consumers can easily compare between providers.
It said all fees associated with setting up, amending or duplicating any type of insurance policy should be "reasonable" and no more than the cost to the company.