London mayor Boris Johnson and Mayor Bloomberg of New York have announced they are to forge a "new era of cooperation" between the two cities.
Mr Johnson also announced the establishment of an exchange programme between London and New York.
The Innovation Exchange Programme will allow officials from both cities to visit each other to share ideas.
In a statement after their meeting at City Hall Boris Johnson said: "Mayor Bloomberg has shown inspirational leadership and I am delighted we are establishing this new era of cooperation.
"I have been particularly impressed by Mayor Bloomberg's achievements in expanding educational opportunities, providing more accountable government and delivering taxpayer value.
"I am looking forward to working closely in the future."
Mr Bloomberg added: "New York and London have a special relationship as two of the world's greatest cities we not only compete with one another, we learn from each other."
Mayor Bloomberg has been credited with cutting crime in New York by 20% during his initial term in office.
Earlier the new London mayor handed his New York counterpart a novelty London Underground shirt in an exchange of gifts.
As Mr Johnson handed over the plastic wrapped shirt he quipped: "This is not the most handsomely wrapped present."
Mayor Bloomberg on the other hand presented the London mayor with a Tiffany box containing a crystal Big Apple paperweight.
Earlier this week Mr Johnson announced an alcohol ban on public transport in London to improve safety and curb anti-social behaviour.
The ban will come into effect on June 1.

Boris Johnson
Mayor of London
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