London mayor Sadiq Khan has said he is concerned a new generation of Londoners are hearing racially offensive terms for the first time.
Following the EU referendum result, the number of hate crimes reported to the Met Police increased from 25-50 a day, to a peak of 88.
Mr Khan said, growing up, his children did not hear the "P, N or Y words" but they were being said once more.
He said he would write to London's head teachers to address the situation.
Since May 2014, the five days with the highest number of hate crime incidents, reported to the Met Police, fell between 28 June and 2 July this year, shortly after the 23 June referendum.
On the Sunday following the referendum result, there were 62 hate crime reports and on the Tuesday, 64.
Mr Khan said: "It's really important that we don't demonise the 1.5m Londoners who voted to leave the EU.
"Nobody is suggesting that just because you voted to leave the EU you're suddenly part of xenophobic or racist crime."
But he said he was concerned the vote had given the impression to some people the result meant they now had permission to racially abuse others.
"We have heard examples of name calling in schools - 'how come you've not gone home yet' - so it's not playground banter.
"I suffered race crime before when I was younger and didn't report it. You've got to report it. The police want to hear from you. From the top [of the police force] to the bottom they care about this.
"It's a crime against the community and against our city."
The mayor made the comments at a London Assembly meeting where he outlined his policing priorities, which included tackling include knife crime, violence against young women and girls, hate crime, sexual offences, cyber crime and preventing radicalisation.