At the Global Mayors Forum, New York's Michael Bloomberg and London's Boris Johnson stressed the importance of economic diversification and dynamism as necessary ingredients for recovery from the financial meltdown.

Mr Bloomberg argued, "A silver lining in Wall Street's contraction is that a lot of ambitious and talented people who, instead of working in big firms, are instead now striking out on their own."

Both mayors were engaged in spirited verbal jousting as they discussed the competitive advantages of their respective cities.

"The city of London does represent infinitely the best starting off place for anybody who wants to export to Europe, anybody who wants to invest in Europe," said Mr Johnson.

"I don't know about London, Boris, but New York has more fashion houses than Paris," said Mr Bloomberg in reply.

The session was followed by a press conference in which both mayors unveiled plans to boost tourism between London and New York over the next two years.

Given their historical linkages, cooperation between London and New York is set to intensify, as both financial epicenters head back to the top.