New research shows that 25% of balance transfer credit card holders are paying a fee to benefit from a zero per cent promotional offer only to see their savings swallowed when they make a small mistake such as making a late payment, which ends the promotional offer.

This is because typically, balance transfer credit card terms and conditions allow lenders to remove the zero per cent promotional offer if a customer makes a late payment, misses a payment or goes over their credit limit.

Once the deal reverts to the lender’s standard offering, cardholders face paying the usual interest rates on their outstanding debt.

Research from The Co-Operative Bank calculates that the average level of debt is £2,105 for the 3 million cardholders who owe money.

And with the average fee paid to switch to a 0% deal standing at 1.37%, this means a staggering £87m has been paid needlessly in balance transfer fees in the last five years by those who have lost their offer early.

Matthew Carter, products and marketing director at The Co-operative Bank, said: “A considerable number of UK credit cardholders lose their promotional offer before they can fully benefit from it, despite paying an initial fee for that offer.”