>> Drug cartel money, strong ties to the Russian oligarchy, forex manipulation, corrupt dealings with African governments, destruction of records, tax fraud.
If anyone is interested in digging into this more, read up on the City of London. Not to be confused with London, the capital of England, the City of London is effectively a weird de facto tax haven city-state embedded in London.
Edit: Somehow managed to write "nationstate" instead of "city-state"
Sounds like HSBC