Until the 1980s, if you wanted to borrow money, you went to a bank or a building society and they made sure you could afford to pay it back. But this was changing, and it changed fastest in the 1980s with credit cards.
Credit cards were very useful because they made it easy to buy things when you did not have the cash to hand. But people began to use credit cards as an easy way of borrowing money. As a result the amount of money people owed grew quickly.