Nazir Afzal claimed Facebook, Twitter and other platforms hinder investigators trying to track down the online abusers. The ex-chief prosecutor for North-west England said: “They place hurdles in front of police and prosecutors trying to get the evidence, which make it really difficult.
He said they should be “policing their own platform” more effectively.
Mr Afzal, who spent nearly 25 years with the CPS, also joined those demanding all social media users must give their real names to sign up to a platform.
He said ensuring those posting under pseudonyms register their identities was a “no-brainer”.
As a prosecutor, he regularly had to go to an American court to force social media firms to divulge information needed for UK criminal inquiries, he said.
The lawyer’s intervention comes as the Daily Express spearheads a campaign to unmask the trolls and wipe the misery they spread off the internet.
He said: “What they’ve forgotten is that with great power comes responsibility.”
A Facebook spokeswoman said: “We have 35,000 people working with sophisticated technology to help keep people safe.”
Twitter said: “We have policies that apply to everyone, everywhere that address threats of violence, abuse and harassment.”