The Metropolitan Police has opened a criminal investigation into alleged antisemitism by Labour members, Scotland Yard has said.
Met Commissioner Cressida Dick was handed a dossier of allegations of Jew-hate in September, after she was interviewed at LBC's Leicester Square studios following the station's investigation into the party's failure to deal with Jew-hate.
The dossier contained alleged Jew-hatred by 45 members of the party, some of whom are now under investigation.
In a statement, the Met said the dossier's contents were examined by "specialist officers".
It said: "A criminal investigation has commenced into some of the allegations within the documentation.
"Early investigative advice is being sought from the Crown Prosecution Service. The MPS will not comment further on the details of our investigation.
Tom Watson, the party's deputy leader, said the news was "thoroughly depressing, though sadly I'm not surprised."
He told BBC Radio Four's Today programme it should "hopefully silence" those who deny Labour has a problem with antisemitism.
The LBC dossier was reviewed by Mak Chisty, a former Met commander who used to run its hate crime unit.
He concluded four of the cases constituted race hate crimes. One of them was a post saying: "We shall rid the Jews who are a cancer on us all." Another referred to "a Zionist extremist MP … who hates civilised people, about to get a good kicking".
Seventeen more could be deemed hate crimes after the investigation.
Board of Deputies Vice President Amanda Bowman said: “This comes as no surprise to us. There is a deeply embedded culture of antisemitism in parts of the Labour Party and Jeremy Corbyn has done close to nothing to address it, to the extent that some cases may now even meet a criminal threshold.
"We have repeatedly set out what Labour needs to do, including taking firm disciplinary action against antisemites and making its opaque processes transparent. Jeremy Corbyn must also apologise for his personal failings to confront racism.”
The Labour Party said in a statement: "The Labour Party has a robust system for investigating complaints of alleged breaches of Labour party rules by its members.
"Where someone feels they have been a victim of crime, they should report it to the police in the usual way."
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