According to The Guardian there is evidence of an abundance of, what Americans call, Ninja mortgages (No Income, No Job or Assets) having been sold in the UK.
These mortgages and debts are, when looked at in the cold light of day, unaffordable by many of the people who are sold them. However, that doesn't seem to have stopped brokers and banks foisting them on the unwary.
The reason for this wanton disregard for financial probity is simple, commission. Brokers are paid a nice fat commission for selling these products, and therefore have a vested interest in selling as many as possible.
Which? claim that the rot set in during the 1980's with endowment mortgages.
Since then, the financial services industry in Britain has been happily destroying its reputation and most probably the economy.