Sadiq Khan, the Mayor of London, said: "I believe that Britain is better off within the European Union, but the British people have clearly spoken today, and their democratic will must now be fulfilled.
"I would like to praise David Cameron for the dignified way he has reacted to the message sent by the British people in his words at Downing Street today. I agree with the Prime Minister that Britain can survive and prosper outside the European Union.
"I want to send a clear message to the British people and to businesses and investors around the world this morning - 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. "Although we will be outside the EU, it is crucial that we remain part of the single market. Leaving the single market of 500 million 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. It is crucial that London has a voice at the table during those renegotiations, alongside Scotland and Northern Ireland.
"We all have a responsibility to now seek to heal the divisions that have emerged throughout this campaign - and to focus on that which unites us, rather than that which divides us.
"I want to send a particular message to the almost one million Europeans living in London, who make a huge contribution to our city - working hard, paying taxes and contributing to our civic and cultural life. You are welcome here. We value the enormous contribution you make to our city and that will not change as a result of this referendum.”