The Mayor of London, Boris Johnson, said: "Last summer the palpable buzz of this great city was beamed across the globe. Since then London's draw has gone from strength to strength with billions of pounds of international investment and huge regeneration projects continuing apace.
"These fantastic tourism figures not only support new jobs and growth in London's economy but are yet another testament to the Olympic legacy."
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David Cameron said the Met proved it can "do more with less" and declined to criticise the Mayor of London for his water cannon spend.
A group of disabled activists threw toys and balls at him as he entered the conference.
A wet start to the week and the unsettled weather is set to continue over the next few days.