The NHS has been accused of being in breach of its stated privacy policy following the sharing of data with Facebook, even though pages do not display the Facebook ‘Like' button.

According to Garlik, both the NHS and Facebook have gone out of their way over the last week to reassure everyone that the NHS's decision to share visitor's personal browsing habits and data via the ‘Like' button was acceptable and consistent with both organisations' published privacy policies.

It pointed out that the NHS privacy policy states: “We only share your information with the data processors, when you visit pages on our site that display a Facebook Like button, Facebook will collect information about your visit.” While Facebook stated: “Only the precise pages of the websites that have the social plug-ins actually transfer data back to Facebook.”

However Garlik claimed that its analysis shows this is not the case and randomly selected pages from the LiveWell section of the NHS Choices site share data with Facebook, yet critically do not display the ‘Like' button. These pages include information on depressionmental health and sexual health.

Andy Thomas, managing director of Garlik, said: “We would of course be interested to hear from the NHS how this sharing can be explained within the context of the previously stated NHS privacy policy. In the meantime we are still waiting for a response to Mischa's original complaint to the NHS.”

The case was originally highlighted by Garlik's Mischa Tuffield, who on his personal blog revealed that the NHS is allowing the likes of Google and Facebook and other sites to track users' NHS browsing habits, regardless of the fact that people use the page to seek medical advice.

In an open letter to the NHS Choices Team, Tuffield said that NHS Choices keeps stating that its privacy policy is correct, but the last few paragraphs of his blog post, that this is not the case. He said: “Do have a look at the following page on your website, there is no 'Like' button and the same data exchange is still happening with Facebook.

“I also talked about how there is a German website which changed the manner in which it implemented the ‘Like' button functionality in a non-intrusive manner. That is, a manner which does not send any information to Facebook unless the user actively clicks (i.e. opt-in) the ‘Like' button; quoting my blog post.”