London mayor Sadiq Khan has sought to reassure business and investors of the city's status, while also noting that the UK's membership of the single market remains "crucial".
Brexit campaigners, including Boris Johnson, have been clear that the UK must detach from the market.
However, Khan said that despite yesterday's Leave vote, the UK should still retain access.
"Leaving the single market of 500m people – with its free-trade benefits – would be a mistake. I will be pushing the government to ensure this is the cornerstone of the negotiations with the EU," Khan said.
"It is crucial that London has a voice at the table during those renegotiations, alongside Scotland and Northern Ireland."
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Khan also sought to reassure businesses, investors and the British people – "there is no need to panic".
"I still believe that our country is better off within the European Union, but there is no doubt that London will continue to be the successful city it is today.
"Our city and our country will continue to be the best place in the world to do business. And we will continue to look outwards and trade and engage with the entire world – including the European Union," he said.
And the London mayor also paid tribute to the contributions of fellow Europeans living in London.
"You are welcome here," he said. "We value the enormous contribution you make to our city and that will not change as a result of this referendum.”