The NHS has allowed four third-party companies to track user activity when visiting its website, according to experts.
Online identity researchers, Garlik, claimed the NHS Choices site lets Facebook and Google, amongst others, know when a user visits "conditions pages" and allows them track their movements across the website.
The user does not have to be logged in to Facebook or their Google account at the time but merely has to have logged in at some point and navigated away from the page without logging out. Facebook and Google can then keep this information for up to 90 days.
Whilst Google claims to just use it for analytics, Facebook can see much more.
"What right has the NHS to share any information about the browsing of NHS Choices with Facebook?," said Mischa Tuffiled, developer at Garlik, who first wrote about the tracking.
"If I walked into a doctor's surgery and said Oh hi, that guy of about 30 who just came in the door, what advice leaflets did he pick up?' there is no way on Earth that they would tell me. Online, the NHS are sharing this information out liberally and the users don't know it and can't opt out of sharing even if they did."
Labour MP Tom Watson has joined the critics of this tracking process and raised the case with secretary of state for health, Andrew Lansley.
In a letter to the cabinet minister, Watson wrote: "The NHS Choices website is used by members of the public in order to find out facts about ailments they may be suffering from and these illnesses could cause an individual embarrassment if the information was leaked."
"We've seen how newspapers like the News of the World have used the digital age to hack into the phones of UK citizens. It would be very embarrassing if people less scrupulous than Sergei and Larry of Google were to know the individual health fears of the nation."
However, a spokesperson from the Department of Health, told our sister title, PC Pro, it was up to the user to ensure they are logged out of other accounts.
"People should log out of Facebook properly, not just close the window, to ensure no inadvertent data transfer," they said.
