An expert has investigated the data that two internet companies possess and warns others on extent of privacy intrusion.

Google and Facebook know almost everything a smartphone owner does online or offline and store the information even if the owner deletes the data on the device, a technical consultant and web developer has written on his Twitter account.

“Want to freak yourself out?,” wrote Dylan Curran. “I’m gonna show just how much of your information the likes of Facebook and Google store about you without you even realising it.”

Here is a selection of points from Curran’s list: