The banking system is one of the most powerful tools the ruling class has at It's disposal. This article touches how the HSBC was involved in laundering money for the drug cartles.

It's an article from the guardian touching many of the cases in which the HSBC has helped the drug cartels in different occassions. I think there was one time in which one of the members of the England branch was openly accused, but nothing was done about it because it "could crash the economy".