Vish I am not sure you are aware but parts of Liverpool are the most deprived in Europe housing and economically with all respect to the residents. London derives almost half of England's wealth and is one of the worlds major capitals probably only New York can compare economically
London is actually the worlds 5th richest city, or has the 5th highest GDP with, New York, Tokyo, Los Angeles and Seoul all with a higher GDP.
Furthermore, not only can you not compare New York and London, you cant compare London to Tokyo either. New York has a GDP of 1.2 billion, Tokyo 1.5 Billion whereas London has a GDP of around 700 million. Half of Tokyo's.