How Google is watching us

So it will probably come as a surprise to find that even if you can't remember where you were on a forgettable Friday afternoon nearly two years ago, there is a good chance that the internet search engine Google can. Every day the site monitors the precise movements of millions of people across the UK, and records them on a map. W here we live, where we work, how we travel between the two, all of this information is painstakingly recorded by the technology giant as it builds up a picture of who we are.

In my case, Google records that I visited a farm on the Welsh border on May 27, 2016, arriving at 3.57pm, and leaving at 5.16pm. My return journey took an hour and 17 minutes – a bit quicker than the journey there, where it looks like I had a bit of trouble with the sat-nav, and later in the evening I visited an address in Albrighton where I stayed from 7.50pm to 9.02pm, before finally arriving home at 9.24pm. The roads must have been clear that night then.

The website has also recorded my precise route to work every day, it recalls that I was visiting a hospital regularly during the spring of last year. It even records me nipping out to Tesco for 21 minutes at lunchtime, although even Google's database does not tell me what I had to eat that day. Yet.

So how is it that my movements came to be tracked in such detail? It is a little known fact that, unless you specifically opt out, that the tech giant monitors the movements of any mobile device which uses its search engine. So if you have a smart phone, a laptop or a computer tablet on which you use Google, there is a good chance that the site is keeping tabs on you. The details are recorded on an interactive map, which can be viewed through the web link google.co.uk/maps/timeline and displays your 21 most-visited locations.

Perhaps less of a surprise is how Google monitors your web activity. Every website you visit, every YouTube clip you watch, and every mobile phone app you download is all carefully stored to build up a detailed profile which could include your location, sex, age, hobbies, career, interests, relationship status, and income. And if you subscribe to the GoogleFit phone app, it also stores data on how many steps you walk too.

This information is hugely valuable to advertisers who want to target you with specially tailored material. Or "improve your Google experience" as it says on the privacy page.

In this respect it is similar to the way Facebook monitors our activities, although Google stresses that the information is solely for the benefit of tailoring its advertising, and personal details are not sold to third parties.

A detailed log on all the information Google has stored on you can be obtained on the link google.com/takeout – but be warned, it will be very big.

Google argues that by helping its advertisers in this way, it is able to provide its hugely popular search services free of charge.

"Much of our business is based on showing ads, both on Google services and on websites and mobile apps that partner with us," says the company's website.

"Ads help keep our services free for everyone. We use data to show you these ads, but we do not sell personal information like your name, email address and payment information."

Google also points out that the information it stores helps it suggest other videos we might like to watch, predicting the things we like to search for, and helping us fill in forms more quickly.

Some people may think this is fair enough. But the worrying thing is how many people are being closely monitored without even knowing about it. It is hard to imagine how the public would ever accept, say, the Government tracking people's movements in this way. Remember the backlash when the Blair government considered introducing ID cards in the wake of the terror threat? Civil liberties campaigners raised understandable concerns about the Government holding so much data about members of the public. Yet against this backdrop Google has quietly been amassing detailed records on our personal movements for years, unknown to the vast majority.

While Google does not pass personal data on to third parties, account holders themselves are able to view it. But although most of us would agree we have the right to view our own data, it does inevitably open the whole process up to abuse. Say, for example you have suspicions of what your wife is doing when you are not around; it would not be difficult to conceal a phone in her car and then monitor her movements using your Google account.

And you do not have to be signed into a Google account to have your details monitored. Even if you are not a registered user, the company can track you through your devices unique registration number, or IP address.

The good thing is, it is still possible to opt out. If you do have a Google account, go onto the map that records your movements, and there is an option at the bottom of the page to "manage location history". And if you go onto your "my account" page you can manage your privacy settings.

As somebody once said, it's time to take back control.