Consumers need better protection against the sharing of their behavioural data between banks, a consumer watchdog chief told The Sunday Times last week, amid fears the information is being used to make “extraordinary profits”.

Since the start of the year, banks and credit card providers have been able to share information about how customers use their cards under an initiative headed by the UK Cards Association, formerly Apacs.

The information is intended to prevent people in financial difficulties from being offered yet more credit.

Even so, consumers have been extended £8.8 billion they didn’t ask for in the past year, according to price comparison website uSwitch.

Ed Mayo, chief executive of Consumer Focus, said more robust safeguards were required to ensure banks and other financial groups were not using the data to offer credit to people who would then accrue higher interest bills.

He said: “It’s high time a regulator, such as the Financial Services Authority, or the Information Commissioner, takes a look at whether there have been any breaches of the code of conduct governing the data-sharing initiative.”

Louise Bond, at uSwitch, said: “There’s a question mark over how these people are selected for an increase to their limit — and if this is in their best interest.”

Separately, a white paper last week moved to ban lenders from increasing credit card limits without consent.

They may also be forced to lift minimum payments levels and be prevented from raising rates on existing debt. Other proposals include a ban on unsolicited credit card cheques.

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