Barclaycard customers who pay off the minimum balance each month could soon be hit with higher interest rates, despite the credit-card provider last week announcing a rate freeze.

The country’s biggest card provider, with 11.9m customers, was applauded for freezing the rates it charges borrowers until June.

However, Barclaycard admitted that for some customers the move was a precursor to rate rises.

It already charges up to 27.9%, with its typical rate being 14.9%, and some customers could see rates go higher from July if they are judged to be risky based on a new data-sharing arrangement.

“We’ll take into consideration a number of different factors — up to 100 different variables — and if these suggest the customer is higher risk, we would change rates accordingly,” said a Barclaycard spokesman.

Until recently, credit-card providers only shared information on cards issued and cancelled, outstanding balances and whether there had been missed or late payments. However, they started sharing “behavioural information” in December — telling each other how their customers use their cards.

It means that Barclaycard might judge a customer paying off only the minimum amount on a rival’s card as higher risk, the spokesman said.

About 11% of all credit-card customers make the minimum repayment each month, according to Apacs, the UK payments authority.

Other behaviour that could result in higher interest rates include making cash withdrawals on a rival’s card.

Apacs hopes the sharing of such data will improve the way lenders judge risk, but consumer groups warn it could mean more customers are denied credit or hit with higher rates.

Steve Willey at comparison firm Moneysupermarket said: “There is always the risk this information could be used inappropriately.”

The new data-sharing will also allow providers to identify unprofitable consumers — those who clear their balances in full every month or switch to 0% deals — even if they have never been their customer.

Barclaycard denies it will use the information to refuse credit to customers who are unlikely to make them money. “This is purely for assessing risk and identifying customers who may need help,” said the spokesman.

Five card providers — Barclaycard, Capital One, HBOS, GE Money and MBNA — initially signed up to the data-sharing agreement. Now all are sharing information, according to Apacs.

Neil Munroe at credit reference agency Equifax said other firms offering credit facilities — mobile-phone companies, loan providers and mail-order firms — also have access to the new information.