There is a growing concern that the Brexit victory to leave the European Union may have triggered an uptick in racially motivated violence or hate crimes.

The National Police Chief's Council has reported an increase of 57 percent in racially charged incidents since the referendum results came in last Friday.

"It's no coincidence this has come off the back of the EU vote," a police source told the Guardian.

Most of the 48.1 percent of Brits who voted to remain in the EU were crestfallen, and shocked, by the outcome. The victory for "Leave" was quickly framed by many anti-Brexiters as a victory for nativists, bigots, and xenophobes.

While there are many reasons besides immigration for why more than half the country opted to leave the EU, there's no question that many Leave campaigners relied on nativist impulses as an emotional trigger, pandering to the tendency to scapegoat immigrants for economic woes in poor, rural areas.

And for those who became riled up by the rhetoric of the right-wing UK Independence Party, Britain First, or by the salacious, xenophobic headlines of Eurosceptic British tabloids, the victory may have emboldened their sentiments. (One headline that ran in The Sun declared: Where the Brex was Won, Streets full of Polish shops, kids not speaking English... But Union Jacks now flying high again.)

Britain's ugliness was laid bare in the run-up to and in the aftermath of referendum – but that doesn't mean it wasn't there before. That a "leave" victory was so quickly equated with bigotry could also mean the public are more attentive to the racism around them, and victims, perhaps fearing this could be the new normal, more willing to report such incidents.

The anecdotes, videos, and graffiti which have emerged so far generally contain the same message — "go back to your own country" — a message which bubbles under the surface of British society and has reared its head once again.

Police have confirmed this shocking incident of racial abuse took place on a tram in Manchester early this morninghttps://t.co/DsqtAhb0dJ

— Channel 4 News (@Channel4News) June 28, 2016

In this video, people are gathered outside a mosque, holding banners saying "Rape-fugees not welcome," waving the English flag and chanting "Allah, Allah, Who the fuck is Allah?":

Another worrying post-#EURef example of bigotry outside a mosque: we cannot allow #Brexit as excuse for intolerance pic.twitter.com/dSCv67YA14

— Miqdaad Versi (@miqdaad) June 25, 2016

In a 2014 survey by NatCen, nearly a third of people admitted to being racially prejudiced, a sharp increase since the turn of the century, and resembling levels last seen 30 years ago. The rise of the National Front in the 1970's and 1980's, a far-right, anti-immigrant group, was then attributed to economic disenfranchisement among working-class whites, who saw immigrants as competition for jobs and scarce housing.

London Mayor Sadiq Khan and the incumbent Prime Minister David Cameron both condemned the reported rise in racist incidents.

"In the past few days we have seen despicable graffiti daubed on a Polish community centre, we've seen verbal abuse hurled against individuals because they are members of ethnic minorities," Cameron told Members of Parliament on Monday. "Let's remember these people have come here and made a wonderful contribution to our country."

Poland's ambassador to the UK, Witold Sobkow, expressed his shock at the "xenophobic abuse" that the Polish community was experienced in the wake of Brexit.

Cards reading 'No more Polish Vermin' left outside homes and schools after EU referendum — BBC News England (@BBCEngland)June 26, 2016

Khan said he had asked police to be "extra vigilant for any rise in cases of hate crime." "Its really important we stand guard against any rise in hate crimes or abuse by those who might use last week's referendum as cover to seek to divide us," he said.

Update: UK police say they caught the three suspects in the tram incident shown above.