A Welsh Muslim woman who campaigned to remain in the EU was told to "pack her bags and go home" soon after the British decided to leave the EU.
Shazia Awan, a businesswoman brought up in Caerphilly, warned that the fallout of the divisive referendum campaign would see an increase in racist abuse.
Echoing Mayor of London Sadiq Khan's view that much of the anti-EU debate had been characterised by hate, Ms Awan had written: "The campaign was racist.
"Don't see how this country can heal itself. The UK is my home yet I feel alienated."
But Warren Faulkner, whose Twitter handle is @foggyneiinfidel, replied: "Great news...you can pack your bags, you're going home...BYE THEN."
His Twitter thread showed other apparently abusive, Islamophobic comments.
Ms Awan, who had campaigned for Remain in Cardiff, said in the aftermath of an anti-immigration rhetoric, the "vile tweets" against ethnic minorities would start.
She said she had witnessed a white man calling a woman a "n*****" in Cardiff after accusing her of voting to remain in the EU. She said the woman had not felt able to report it as a hate crime.
"Every ethnic minority, every decent person, everyone who is in a mixed race relationship or from a black, Asian minority ethnic background are going to feel this now. Now start the vile tweets,” she said.
During the campaign, Nigel Farage and his Ukip party were reported to the police for allegedly inciting racial hatred with a poster showing refugees "queuing" to get into Europe.
Refugees from Africa and the Middle East are fleeing brutal civil war, dictatorships and poverty.
Sadiq Khan, new Mayor of London and Remain campaigner, told his predecessor Boris Johnson during one referendum debate that the Brexit camp's claims it was not simply "anti immigrant" were disingenuous.
"You might start off with platitudes saying how wonderful immigration is. But your campaign hasn't been Project Fear. It's been Project Hate, as far as immigration is concerned," he told Mr Johnson.