Hundreds of thousands of credit card holders enjoying interest-free borrowing face a potential payment shock as cautious lenders reduce the number of zero per cent deals on offer.

The number of companies with zero per cent offers on balance transfers – where the card holder moves debt from one company to another – has fallen by nearly 10 per cent in the past year, according to new figures. Just 75 per cent of credit card providers now offer one of the deals, with a total of 97 deals on the market, down from 82 per cent, or 103 deals, in October 2007.