I believe it is more the case that the banking sector in the City of London is the institution, and the secrecy jurisdictions are tools that it developed and uses. Historically money ended up in England because of the Eurodollar system, and from there banks use the secrecy jurisdictions to create trust systems across different jurisdictions for opaqueness. England as an intermediary is preferred because there is a level of trust there with their institutions that isn't there with some bank in a random backwater.