It claims the rate on authorised overdrafts is at its highest level since records began in the mid-1990s.

According to the latest Bank of England statistics, the average overdraft rate is 18.96%, although many of the big banks can charge considerably more.

Which? says that the rate for unauthorised overdrafts has fallen owing to a major court case.

It has accused banks of raising the rate on authorised overdrafts to make up the difference.

“It is like a balloon,” says Phil Jones, of Which?. “When you push in one part, it comes out in another.”

“So we see that the banks are consistently taking sneaky ways to make money out of people.”

Many banks have reduced the rates on unauthorised overdrafts.

On 1 October, the Royal Bank of Scotland cut its charges. On 1 December, the Halifax will restructure the way it charges customers, which will benefit some people with an overdraft.

In relation to high rates on authorised overdrafts, the industry argues that its own costs remain stubbornly high.

The British Bankers’ Association (BBA), which represents the banks, is reminding everyone that the cost of borrowing no longer tracks the Bank rate as it once did.

Instead banks have to borrow money on the more expensive wholesale market. The risk of borrowers defaulting is also higher than it was.