NHS trusts have been sharing the private medical information of patients with Facebook via a covert tracking tool on their websites, a probe has found.

The tracking tool was being used by the webpages of 20 NHS trusts to collect browsing information before sharing it with tech giant Meta, Facebook's parent company.

The major privacy breach, uncovered by The Observer, included intimate details about patients' medical conditions, appointments and treatments.

Data obtained by the Meta Pixel tool could then be used by the social media giant for business purposes, including targeted advertising.

The probe found 17 of the 20 NHS trusts using the tool, which serve more than 22 million patients in England, had pulled the tracker from their websites over the weekend.