Speaking to Sky News, James Ducker - a former employee at HBOS and Lloyds TSB, part of Lloyds Banking Group, the largest retail bank in the country - suggested lenders bent the rules with regard to products known as 'swaps', which refer to an institute and customer exchanging loan payments.
Investors claimed they were not fully informed of the risks that exit fees and low interest rates would pose.
Mr Ducker said the items were sold without due consideration for the consequences should rates dip, noting: "The bank was protected more than the customer and it was normal practice to emphasise the rewards and de-emphasise the risks."
The industry figure described the pressure to offload these products as "immense", observing those selling them were not mitigating a customer's exposure, adding the practice was similar to giving an individual an umbrella before taking it away.
By Asim Shah