Sir Tim was speaking as it emerged that the US government has been collecting huge amounts of personal information from Google, Facebook, Apple and other internet companies.
There have also been reports that British spies have been gathering intelligence from the internet giants "through a covertly run operation set up by America's top spy agency"
“Unwarranted government surveillance is an intrusion on basic human rights that threatens the very foundations of a democratic society,” Sir Tim said. “I call on all web users to demand better legal protection and due process safeguards for the privacy of their online communications, including their right to be informed when someone requests or stores their data.