How many people in the UK remember the Big Bang? Well, the Big Bang occurred a few decades ago, and represented a radical change in the way high street banks and other financial entities could operate in the UK, allowing them greater scope to enter new markets and offering foreign financial entities increased room to do 'their thing.' The problem with this whole process was that some of the foreign banks were American, and doing their thing is very different from the way things are normally done in London. You might as well say that their is no rule book because in the States if it isn't illegal and it can make you money, you go out and do it. Perhaps, you do some of the illegal things as well. Innovation in finance begins in America, after all, they have the moxy.
It was a measure to increase competition and its resulted in banks competing directly with building societies for the business of home loans and mortgages. With this change, the building societies essentially transformed themselves into banks.
Of course, the British banks were delighted because they could engage in the business of longer term lending and make huge profits without as much risk as lending to business, which they were frightened to do. Actual lending to business outside of the housing market is risky or didn't you know. And, so ended the protective shield associated with mortgage lending.
Now the world, and especially Britain, has caught a Stateside disease of profligate lending, it looks as though we will go through all the symptoms of this disease. We could, as the authorities are now doing, pretend the disease can be fed and driven away, but that is not to understand the nature of the disease. No, to get to the disease the protective shield for the consumer must come up again, and a higher penalty for profligate lending charged. Yes, interest rates will have to rise!