The report by the UK Parliament Home Affairs committee found — following a 12-month investigation — that the companies have teams of "only a few hundred employees" to monitor networks of billions of accounts and Twitter does not even proactively report extremist content to law enforcement agencies.
"If they continue to fail to tackle this issue and allow their platforms to become the 'Wild West' of the Internet, it will erode their reputations," the report said.
"They must accept that the hundreds of millions in revenues generated from billions of people using their products needs to be accompanied by a greater sense of responsibility and ownership for the impact that extremist material on their sites is having," the report said.
Internet giants "consciously failing" to tackle extremism on the web: Home Affairs Committee report on radica… https://t.co/JIHvr79iMi— Home Affairs Cttee (@CommonsHomeAffs) August 24, 2016
"We are engaged in a war for hearts and minds in the fight against terrorism. The modern front line is the Internet. Its forums, message boards and social media platforms are the lifeblood of Daesh and other terrorist groups for their recruitment and financing and the spread of ideology," Keith Vaz MP, Chair of the Committee, said.
"Huge corporations like Google, Facebook and Twitter, with their billion dollar incomes, are consciously failing to tackle this threat and passing the buck by hiding behind their supranational legal status, despite knowing that their sites are being used by the instigators of terror," Vaz added.
"Even when someone is convicted, such as [British Muslim social and political activist] Anjem Choudary, their videos and hateful speeches continue to influence people through these websites. The companies' failure to tackle this threat has left some parts of the internet ungoverned, unregulated and lawless."
The report recommended that the British Government build on the work of the Metropolitan Police's Counterterrorism Internet Referral Unit (CTIRU) which provides a "vital function" in combating online extremism.
It says the CTIRU should be upgraded into a high-tech, state-of-the-art round-the-clock central Operational Hub which locates the perils early, moves quickly to block them and is able to instantly share the sensitive information with other security agencies.