British police announced yesterday they were investigating alleged "anti-Semitic hate crimes" within the main opposition Labour Party after receiving a leaked internal dossier.
The criminal investigation comes after a national radio station obtained what it said was an internal Labour document detailing 45 cases involving messages posted by party members on social media.
Labour, led by veteran socialist Jeremy Corbyn, spent the British summer dogged by accusations of anti-Semitism.
The issue has bubbled under the surface for years, but intensified in recent months with a series of incidents coming to light.
"A criminal investigation has commenced into some of the allegations within the documentation," London's Metropolitan Police said in a statement.
Britain's top police officer Cressida Dick was handed the leaked dossier two months ago after an interview at LBC.
"The complainant alleged that the documentation included evidence of anti-Semitic hate crimes," the Met Police said.
"The contents have been examined by specialist officers."
The Met said early investigative advice was being sought from the Crown Prosecution Service.
The CPS, England's state prosecutors, decides on whether to bring criminal charges once an investigation is complete.
LBC had previously showed the dossier to former senior Met Police officer Mak Chishty, who had been in charge of dealing with hate crime.
He believed that 17 instances should have been reported to the police for investigation, and another four were potential race hate crimes.
Dick said Labour as a whole was not under investigation.
"We are not going to investigate the Labour Party. We would always want institutions and political parties and similar to be able to regulate themselves," she told BBC radio.
"However, if somebody passes us material which they say amounts to a crime we have a duty to look at that.
"We are now investigating some of that material because it appears there may have been crime committed.
"I hope we will be able to clear that up very quickly."