Not so long ago "subprime" was a word to strike fear into the hearts of bankers everywhere.

Risky mortgage lending to people with poor credit ratings - who eventually defaulted on their debt - was the main trigger of the 2008 financial crisis.

But are the banks back to their old ways? Subprime lending is booming once again in the US - not for home loans, but for cars.

According to the credit agency Experian, the total amount owed on car finance in the US had risen to $750 billion by late last year.

An estimated 36% of those loans have been made to subprime borrowers. So are the banks storing up serious trouble for the future - and maybe even another financial crisis?