The line between private and public life has been blurred as a result of the internet revolution, leaving many people's personal information open to use – or abuse – by businesses, hackers and spies.
Disclosures about data monitoring by intelligence agencies, including reports that millions of webcam images had been harvested by Cheltenham eavesdropping station GCHQ, have triggered a political row about the way the activities of Britain's spies are regulated. But with so much information shared voluntarily on social networks such as Facebook and Twitter, it is not only the intelligence agencies who take an interest in our online activities.
Nick Pickles, director of privacy campaigners Big Brother Watch, said: "I think the web has transformed the way we live our lives, and one of the side effects of that communication is that far more information about what we are doing, who we are talking to, what we are buying, is out there."
The leaks by whistleblower Edward Snowden, which gave an insight into the activities of both the US National Security Agency and its British counterpart GCHQ, have led to calls for far tougher restrictions on the activities of the intelligence services. Mr Pickles said one of the problems was that the rules governing the interception of communications were "laws for a copper cable world in a fibre optic age".
There was no longer a distinction between foreign and domestic communications, he said, as an email sent to a colleague sitting next to you in an office could be routed through servers overseas.
Politicians at Westminster are grappling with the issues raised by the technological advances which have given GCHQ access to "bulk data" about internet users.
Mr Pickles said it was not surprising that there was a demand for as much information about people as possible. "I have heard of foreign states asking for people's Facebook passwords when they turn up at the border," he said.
People making applications for jobs, insurance, healthcare or bank loans could also have their online profiles examined by those making the decisions, he added.
There was now a tension between the "thirst for information from national governments and companies" and a public with a growing concern about their privacy online.
The difficulty lies in making sure that the "inherent openness of the web does not get stifled", Mr Pickles said. "That tension will always be there."