GCHQ has warned David Cameron that internet companies including Facebook and Google are undermining national security, it has been reported.
The Prime Minister was told internet giants have “withdrawn” their cooperation and are obstructing MI5 requests for help tracking terrorists and major criminals, including paedophiles, according to The Mail on Sunday.
This follows fugitive Edward Snowden’s claims that the firms are used to snoop on British citizens, which is disputed by spy chiefs.
Before the US whistleblower’s disclosures, they willingly responded to lawful requests for details of phone calls, emails, text messages and other private information.
Now the companies are said to be concerned about being seen to help Cheltenham-based listening post GCHQ and other agencies too easily, the Mail reports.
One of the fears is that intelligence officers will lose the ability to monitor the safety threat posed by British jihadists travelling to Syria.