John Borgars of Equity Development claims that the households would be unable to cope if they were hit by unexpected illness, injury or redundancy.
“For the last eight years, Britons in aggregate have been spending more than they earn resulting in a gradual build up to a vast number of individual crises,” warned Mr Borgars.
His comments come from his study of the Financial Services Authority’s figures, which is also backed up by other data.
The charity Credit Action claims that two million people are overdrawn as soon as they are paid on payday and 3.5 million are permanently overdrawn, meaning that they are the most at risk.
With unsecured borrowing on credit cards and other loans rising, Mr Borgars warned that millions of people are at risk of debt because they have not made plans for disasters.