Reports of hate crimes have soared by 400% since the UK voted to leave the EU on 23 June, according to new figures released by the police. The National Police Chiefs' Council (NPCC), which runs the True Vision online reporting website, said in the week since last Thursday's vote they had received 331 hate crime allegations compared with the usual average of 63.

NPCC Chairwoman Sara Thornton urged caution between linking the apparent surge of hate crimes to the referendum, saying it was hard to prove any direct connection. She also said one reason for the rise in reports may be down to the fact that people were more aware of hate crimes due to the number of reports circulating in the media and online.

"It is important to remember that this [website] is only one reporting mechanism and extensive focus on this issue in the last few days will have influenced these numbers by making hate crime and the site more visible and encouraging people to report," said Thornton. "We also cannot determine how many of the reports are linked to the referendum."

Thornton condemned those responsible for a number of incidents including physical abuse, racist graffiti and anti-migrant leafleting. The police would investigate every claim, she said, and those affected should report any incidents and not "suffer in silence." One way to report hate crime is to visit the True Vision website.

A number of incidents have been reported widely in the media including the spray-painting of a Polish community centre, vandalism of German cars and anti-Polish leafleting. There have also been a number of videos posted online which appear to show racist attacks, usually verbal. Many people – not just immigrants but also Britons perceived as being from a "different" heritage – are using the #PostRefRacism hashtag to report and publicise incidents.