Barclaycard, the largest credit card in the UK with almost 10 million customers (15% of the market), is to charge a fee to penalise customers who do not use their cards enough and to encourage them to spend more.

If it is introduced, the fee could be imposed on “low usage” customers – that is, people who only use their cards infrequently or not at all. Some observers have suggested that £20 is the level at which the fee would be charged

Barclaycard is writing to one million of its customers in order to try to get them to use their cards more frequently and therefore avoid the fee.

“We will do everything we can to improve the deal we give people, encourage them to use our card and not someone else’s and avoid fees,” said a spokesperson for Barclaycard.

“As a last resort, we are considering a fee for a minority of customers that simply do not use their card.”

But Barclaycard holder Mike Busby is against the move. “It depends on what Barclaycard calls ‘low usage’ and how it will apply the fee,” he said.

“I only use my card a couple of times a month to buy petrol and always pay off the balance. Will I be penalised for doing that?”