The City of London; a state within a state?

I attended a lecture at the LSE recently that dealt with the City of London and its network of tax havens, absolutely fascinating and very topical!

The two speakers were Nicholas Shaxson, the author of  "Treasure Islands: tax havens and the men who stole the world" and Maurice Glasman, recently appointed Labour Peer and Reader in Political Theory at London Metropolitan University. and their basic premise is that the 'city' is basically an un-democratic 'state within a state', a bit like the Vatican I suppose?, which flouts regualtions and rules and feeds itself through a network of tax havens (Hong Kong, Bermuda etc). Tax havens allow the city to make huge amounts of money through tax avoidance and using loopholes in legislation. They are secretive and unregulated.