This is a very interesting potential Precedent, perhaps.

 Under the Plevin rule, if more than 50% of a consumer’s PPI’s payments went as commission and this was not explained to them at the time, they could claim back payments above that threshold, plus interest

What I'm seeing there is the idea that if someone enters a contract but it is one in which they are exploited in such a way that the other party makes excessive profit, then they are entitled to money back. Now play that through the idea that workers in various industries have had wages depressed while business owners, shareholders etc have taken excessive commission ...

UK banks could face new multibillion-pound claims after PPI ruling | Money | The Guardian: