Sadiq Khan has revealed some of his friends suffered vile racist abuse after Britain's vote to leave the EU.
But the Mayor insisted that people should not be labelled as bigots purely because they voted for Brexit or US President-elect Donald Trump.
Mr Khan told how friends of his were called the 'N-word' and slurs such as 'p***' in the weeks after the referendum.
The Remain campaigner said the social and political divisions stirred up by the debate around EU membership have caused him concern.
Speaking to the website Politico, he said: “Whereas it was not uncommon when I was growing up to hear the ‘p’ word or the ‘n’ word or the ‘y’ word, depending on whether you were Asian, Afro-Caribbean or Jewish, my kids have never been racially abused in that way.
"But friends I have spoken to of my age post-Brexit have heard the ‘p’ word or the ‘n’ word or the ‘y’ word… I’ve got mates who were called the ‘n’ word or the ‘p’ word in the week or two after Brexit.”
Mr Khan also criticised Trump’s comments on Muslims in the US campaign, accusing him of making both Britain and America “less safe” and playing “into the hands of the extremists”.
But the Mayor of London added: "Don’t call people racist because they decided to vote for an alternative, radical path.
“Try to understand the concerns they’ve got an try to address them.”
He said liberal parties in Europe and the United States need to find a way of better getting through to angry voters who feel they haven't benefitted from open trade and globalisation, or risk losing them permanently to populist candidates or parties.
Following the Brexit vote, Mr Khan said his focus is now on trying to protect London’s position as an international financial, commercial and cultural center.
He has been a leading voice against a so-called hard Brexit, with a key concern being access to the single market for British business and the City of London.
He said: “We’ve got to make sure the government has a clear plan but telegraphs that it has a clear plan to give reassurance to businesses and others.
"I’ve had no complaints about the access I’ve had or how receptive the secretaries of state have been toward me, but the proof is in the pudding.”
