British police have launched a criminal investigation into allegations of anti-Semitic hate crimes within the opposition Labour Party.

The Metropolitan Police said Friday that it is acting on a dossier of information given to London police chief Cressida Dick. A police spokesperson says it was handed to her following an interview on LBC Radio.

LBC had in its possession an internal Labour Party dossier that detailed 45 cases that involved social media postings by party members, including one posting that read: "We shall rid the Jews who are a cancer on us all."

The police statement said the person making the complaint "alleged that the documentation included evidence of anti-Semitic hate crimes. The contents have been examined by specialist officers. A criminal investigation has commenced into some of the allegations within the documentation."

Dick told BBC Radio there is evidence a crime may have been committed based on the material given to her.

"If somebody passes us material which they say amounts to a crime, we have a duty to look at that and not just dismiss it," she said.

Dossier received 2 months ago

Police did not provide details about the possible hate crimes detailed in the dossier.

Labour Party leader Jeremy Corbyn has been dogged for years by complaints about anti-Semitism within party ranks. He has said the party deplores all forms of racism.

Labour Party officials say the party has not been contacted by police but is ready to co-operate.

The party released a statement saying it had "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," a Labour statement said.

'No role' for hate crimes in party

Labour's deputy leader Tom Watson said the allegations were "thoroughly depressing — although, sadly, I'm not surprised."

"If people have committed hate crimes, then they need to be dealt with by the full force of the law. There's no role for them in the Labour Party," he told BBC Radio.

A report in February by the Community Security Trust, a charity that provides security advice to the country's Jewish communities, said anti-Jewish sentiment was becoming more commonplace in Britain.

It said publicity about alleged anti-Jewish sentiment in the Labour Party had been partly to blame for a record number of anti-Semitic incidents in Britain last year.