However, Egg is not alone. Royal Bank of Scotland does it too, and perhaps there are others.

More worrying is the trend for interest rates to be ramped up steeply, especially when a borrower has a nice juicy balance which they are unlikely to be able to pay off quickly. This is of course a response to the credit card companies being forced to reduce their penalty charges, and does rather prove that the charges were not merely a deterrent, but a lucrative source of income. The difference is that a penalty charge is effectively a voluntary fee, easily avoided, while increased ongoing interest for an existing borrower is not.