As Lib Dems we have campaigned long and hard for curbs on the government’s power to snoop on our internet data.

Yet, most of us (not all) have personally given an eye-wateringly broad “Snoopers’ Charter” to big corporations – namely Facebook and Google.

I know, I have checked on my data held by Facebook and Google. You can do it too. Facebook had all my photos, posts, friends etc etc going back to February 2007. The data was 354 megabytes in size. That’s equivalent to 71 copies of the Complete Works of Shakespeare.

Google is in another league altogether. They hold of 28 gigabytes of my data. That’s equivalent to the data on 28 large lorries stuffed full of books. 28 of them! I am still downloading the data they hold for me. It has taken me two days just to download a tenth of it. They had records of search terms which I used in 2007.

The interesting thing is that, in this situation, there is only one person to blame. Me. (Or you, if you have done the same – us). I am responsible for handing over my data to Facebook and Google. I confirmed that I read their terms and conditions, I hit “yes” to agree to endless handovers of contacts and personal details.

OK, it is absolutely true that Google and Facebook have some culpability for basing their business models on monetizing vast tracts of our data, based partly on the average person’s gullibility.

(A lot of this has been made possible by cheaper computer storage hardware. I have been inside several Data Centres. Most people don’t know they exist. They are usually very nondescript buildings, with very little signage, in very humdrum areas. Inside they have rows and rows and rows of storage capacity. This advance in miniaturised data storage underpins the revolution in corporately-held personal data. It is comparatively cheap, nowadays, for corporations to use acres and acres of data storage machines to store mind-boggling amounts of our data. Such a revolution is well beyond our imagination, so therefore it is a surprise to most people that it has happened.)

So, it is right that Facebook and Google are facing renewed scrutiny.

But it starts with you and me. If you have a Facebook or Google account, then download your data which they hold. Have a look at it. It is guaranteed to make your hair stand on end.

Once you have done that, you might like to join me in deleting your Facebook account. (I am still working on Google). That is the only real way to delete the data Facebook hold for you. What you can then do is leave it a few weeks then, if you wish, set up a new Facebook acocunt, but this time do it with your eyes wide open, aware of the consequences and the settings which allow you to make big decisions about your data.

* Paul Walter is a Liberal Democrat activist. He is one of the Liberal Democrat Voice team. He blogs at Liberal Burblings.