Keir Starmer has confirmed he has received death threats after Boris Johnson's false claim that he failed to prosecute Jimmy Savile.
The Prime Minister has failed to withdraw the slur he made in Parliament against Mr Starmer despite furious criticism from Tory MPs.
The Labour leader was accosted by a mob of anti-vaxxers in Westminster last week, with some protesters shouting "paedophile protector".
He was bundled into a police car by officers.
Police have launched an investigation into online death threats made against Mr Starmer after the PM's false claim that he failed to prosecute the notorious paedophile when he was director of public prosecutions.
Documents, including a batch of messages from users of the Telegram app who appear to be identifiable, were sent to Scotland Yard by the Centre for Countering Digital Hate (CCDH) on Friday.
A Metropolitan Police spokesman said: "On Friday 11 February, police received a third party report relating to allegations of malicious communications made against a serving Member of Parliament. An investigation is ongoing."
No arrests have been made.
Asked if he had received death threats, Mr Starmer told BBC Newcastle: "Yes, I do not like talking about this because I have young children.
"It's very important for me to say that what the PM said was wrong, it was very wrong, he knew exactly what he was doing.
"There's been a right-wing conspiracy for some time that is a complete fabrication. He fed into that.
"That has caused difficulty but my preference if I may is not to talk about that because as I say I've got young children and I don't particularly want them to hear too much of what may or may not be said about me."
Mr Starmer said he went to play football after he was confronted by protesters last week.
A Labour source said: "Of course extremists of all stripes don't like Keir - he spent years helping to put them and their ilk in prison and keep Britain's streets safe from them."
The material from the CCDH, shown to The Observer, includes responses to footage of last week's incident posted by English Defence League founder Stephen Yaxley-Lennon - better known under his pseudonym Tommy Robinson - and conspiracy theory group Resistance GB.
Mr Starmer was head of the Crown Prosecution Service in 2009 when a decision was taken not to prosecute Savile but he had no personal involvement.
The Labour leader blamed Mr Johnson for the confrontation outside Parliament last week, saying he had never been called a "paedophile protector" before.
He told the Times: "If others want to argue that this is unconnected with precisely what the Prime Minister said one week before then let them make that case.
"But they'll never persuade me that there is no link."
Mr Johnson tweeted that the "behaviour directed" at the Labour leader was "absolutely disgraceful" - but failed to apologise for his words.
A string of Tories urged him to withdraw the remark, with Chancellor Rishi Sunak saying: "I wouldn't have said it."
Downing Street condemned the death threats.
Asked if the PM felt responsible, his spokesman said: "I haven't spoken to him on that specific point this morning. Obviously any sort of death threats to politicians are never acceptable."
Mr Johnson declined to comment on a visit to Scotland, telling reporters: "I've said more than enough about that issue."
