What with all the CCTV cameras, I already knew I was being watched in the street. But I had no idea till now that I was under surveillance at home. The faceless, nefarious collectors of data are watching — how I use the phone and who I’m calling. They know what websites I visit when I’m online. They are preparing to check out my medical records. By watching my shopping, they already know what I eat. They even know what I wear in bed.

The technology permitting them to do this has not been put into place by an evil power, I am told by Richard Thomas, the information commissioner, which is some comfort, but he did warn last week that we are “waking up to a surveillance society” and that Britons are the most spied-on people in the western world.

Thomas, 58, a lawyer who formerly worked for the Citizens Advice Bureau, the National Consumer Council and the Office of Fair Trading, has just published a hefty report on how data is gathered on everyone. “We have been quite surprised, frankly,” Thomas says when I meet him. “When you pull it all together and see the impact on daily lives of us all . . . I have been disturbed by what I have read. And I think a lot of people will say, gosh.”

We are monitored as citizens and as consumers. Our movements are tracked and our private thoughts logged. If someone with a bit of money has a grudge against you, there’s little to stop him hiring a private detective to get hold of electronic records covering every aspect of your life.

The argument that if you have nothing to hide you have nothing to fear is described by the report’s authors as “fallacious and dangerous”. If you know you are being watched you change your behaviour. Do you close the door when you go to the loo? Do you resist the urge to pick your nose while others are present? If so, you are a normal human being. You are also, like it or not, a privacy advocate. And these are just the things that everyone agrees on. (Well, nearly everyone. I can think of exceptions.) Conspiracy theorists say that watching people is a form of social control. They are not entirely wrong and it seems that we are increasingly unable to refuse our consent. At work, some employers track keystrokes to monitor staff use of computers, or use GPS to monitor company vehicles.

Even those that do not do this have policies entitling them to access electronic records relating to phone and computer use. That’s fine, until the employee falls out with the company — which may then legally trawl through the records for anything even mildly incriminatory. Few of us would come out of that looking good.

We do not choose to be monitored by the 4.2m CCTV cameras — more than in any other country. The Home Office has admitted that “the CCTV schemes that have been assessed had little effect on crime levels”. But more cameras are coming: in future they will be mounted on unmanned drones flying overhead.

We don’t ask to have our vehicle movements logged by automatic plate recognition, or information from our use of Oyster cards on London transport passed to the police — a classic instance of “function creep”, in which data collected for one purpose is used for another, usually without consent.

People who have been arrested do not choose, and are often coerced, into providing fingerprint and DNA samples that will be permanently logged on the national database even if they are released without charge. When Grant Shapps, a Tory MP, challenged this on behalf of a constituent whose son had been mistakenly identified, the police told him they were not authorised to remove the boy’s data. Sir Alec Jeffreys, a pioneer of DNA profiling, says hundreds of thousands of innocent people are populating that database. There is increasing evidence that the data is being used to carry out controversial genetic research without consent.

Another group put under surveillance before they are convicted are the thousands of adults and juveniles, some as young as 12, tagged to await trial at home rather than be put in custody. Some of them, let’s not forget, may be innocent. Jean Lambert, the Green MEP, points out that anti-nuclear protesters arrested at Faslane naval base but never charged were subsequently refused entry to Genoa during the meeting of the G8: “The information about their arrest should not have been kept, let alone circulated abroad. What redress can they have now the information has been passed around?” If part of you suspects that these people deserve to be watched, regardless of their innocence, remember that in May the Criminal Records Bureau admitted that it had wrongly labelled 2,700 innocent people as pornographers, thieves and violent criminals.

If it’s bad enough being watched, it’s worse still if you don’t know it’s happening. Even at home a record is kept of every website we visit. In August, AOL accidentally released search inquiries from 20m users. Supposedly shorn of identifiers, it took only moments to start connecting search records with names.

One who was identified was a man in Florida who typed his troubles into the search window of his computer: “My wife doesnt love animore”. He searched for “Stop your divorce” before turning to self-examination with “alcohol withdrawl sintoms” (at 10 in the morning) and “disfunctional erection”. Some days later he typed: “My cheating wife” and then, five times, “I want to kill myself” and then “I want to make my wife suffer” followed quickly by “Kill my wifes mistress”. Two days after that, with an irony I wouldn’t dare to invent, he was looking for audio surveillance and bugging equipment.

You don’t need to be an alcoholic with a broken marriage to worry about your emotional problems becoming publicly available. We ask Google things that we would hesitate to ask anyone and Google remembers it all. Roger Clarke, an Australian specialist who lectures worldwide on “dataveillance”, is particularly critical of Google. The Google Desktop service, he says, is promoted as a device to search your own hard drive with no suggestion that Google can access the data:

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