Moving home is the biggest financial burden with nearly one in five people claiming that it was responsible for an increase in their borrowing.

But 16 per cent of people interviewed for research carried out for the Money Advice Trust cited school fees as the main cause of their problems.

Annual boarding fees in prep schools range from pound;8,400 to pound;13,500. Boarding in boys’ and girls’ senior schools costs between pound;10,200 and pound;18,000 a year.

Nearly one in 10 adults in the UK said their debt levels had increased in the past six months.

Only 12 per cent of people claimed their debt was getting worse as a result of losing their job. Just 1 per cent more blamed the cost of home improvements, and 2 per cent more the expense of having a baby.

Alan Jarvis, director of Money Advice Trust, said: “While the majority feel they have their borrowings under control, nearly two million people admit they were taken by surprise when their debts increased.”

Dick Davison, joint national director of the Independent Schools Council information service, said: “It is hardly surprising that parents are getting into debt.

“We do know there are a large number of people who make enormous financial sacrifices to pay school fees.

“We also know that the majority don’t plan ahead for school fees and fail to take preventative action, such as taking out policies in advance to maximise their available funds.”