More than 3,000 incidents were reported to police across the country between June 16 and 30, up 42 percent on the same period last year, according to the National Police Chiefs' Council.
"We now have a clear indication of the increases in the reporting of hate crime nationally and can see that there has been a sharp rise in recent weeks," said Mark Hamilton, the council's lead officer on hate crime.
"This is unacceptable and it undermines the diversity and tolerance we should instead be celebrating."
But anti-racism campaigners had previously reported a surge in attacks, from verbal abuse to physical attacks, in the days after Britain's vote to leave the EU.
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Prime Minister David Cameron had raised the issue in parliament, citing "despicable" graffiti daubed on a Polish community centre and abuse directed at members of ethnic minorities.
"We will not stand for hate crime or these kinds of attacks, they must be stamped out," he told lawmakers.
There was a peak in reported offences on June 25, the day after the referendum result was announced, when there were 289 incidents. The numbers have since declined.
On Thursday, envelopes including messages of abuse and white powder were sent to several London mosques and a Muslim member of the House of Lords, sparking security alerts across the capital.
"There are a lot of very frightened communities in Britain," opposition Labour leader Jeremy Corbyn said in a speech to a pan-European socialist conference in Paris.
Nils Muiznieks, human rights commissioner for the Council of Europe -- a European forum on democracy and rights -- on Friday condemned the "racist rhetoric" that emerged during the Brexit campaign.
The Syrian refugee crisis also featured in the debate. The Brexit camp issued leaflets and an online video warning that tens of millions of Turks would be on their way if Turkey joined the EU.