"There is no question the UK is shifting to a more racist atmosphere and policies. This is a rhetoric that's showing up in the lives of schoolchildren," said Adam Posen, a former member of the Bank of England's Monetary Policy Committee who now leads the Peterson Institute for International Economics.
"We're legitimising politics and politicians that play with racism in a much more dangerous way than Richard Nixon ever did."
British politics are in chaos after the vote in favor of a so-called Brexit prompted the resignation of Prime Minister David Cameron, spurred a rebellion against Labour Party leader Jeremy Corbyn, and opened the door to a second referendum on Scottish independence.
The Leave campaign's message was centered on reducing immigration, including by raising the specter of Turkish membership in the EU - a prospect European diplomats say is remote at best.
A week before the referendum, UK Independence Party leader Nigel Farage unveiled a billboard showing a column of hundreds of refugees walking on a road, under the heading "Breaking Point."
Some incidents are occurring in the heart of the UK's cosmopolitan capital.
Sebastien, a 26-year-old Frenchman, was walking in the Kensington district on Friday with a friend and her mother, who was visiting from Paris. Hearing them speaking French, a man walking his dog began shouting at them to "Leave, Leave!," Sebastien said, who declined to provide his surname for fear of retaliation.
Schoolchildren were racially abused in a west London district this week, Seema Malhotra, one of the main opposition party's team of Treasury spokespeople said on Saturday.
"Someone shouted: 'Why are there only 10 white faces in this class? Why aren't we educating the English?'" she said, citing a letter from a teacher in her electoral district about an incident on Wednesday. "Another went close up to the children and said: 'You lot are taking all our jobs. You're the problem."'
Speaking to the BBC on Sunday, former Prime Minister Tony Blair said political leaders "have a big responsibility to help our country get through what's going to be an agonising process."
After a vote that largely pitted London, Scotland and a few other enclaves in favour of staying in the EU against the bulk of England and Wales, "we have a divided country but there is the possibility of bringing people back together if we are sensible about it."
Britons have taken to Facebook and Twitter to report other racist incidents.
One user, Fiona Anderson, described "an older woman on the 134 bus gleefully telling a young Polish woman and her baby to get off and get packing."
A professor at Coventry University, Heaven Crawley, said on Twitter on Friday that "This evening my daughter left work in Birmingham and saw group of lads corner a Muslim girl shouting 'Get out, we voted leave'."