Hundreds of thousands of people are having their confidential NHS patient data shared against their wishes, it has emerged.
Requests from up to 700,000 patients for details from their records not to be passed on organisations including insurance companies have not been met.
The details were registered during preparations for the creation of a giant medical database.
Patients registered their objections during the development of the controversial care data system but the plans were shelved in March 2014.
In February, the Health and Social Care Information Centre (HSCIC) told MPs it "does not currently have the resources or processes to handle such a significant level of objections" and it also had technical issues over logging the preferences.
Phil Booth, director of data rights advocacy group medConfidential told health sector journal Pulse: "The material fact is, hundreds of thousands of people, last January, February, March,exercised their right to opt out of having their data passed on by the HSCIC,and that has not been respected.
The HSCIC is committed to ensuring no patient suffers any adverse impact on their direct care through an inappropriate implementation of an objection. This means that information for applications such as cancer screening, electronic prescriptions and e-referrals is currently flowing and will continue to do so. The HSCIC is working closely with NHS England, the Department of Health and the National Data Guardian to progress these issues and ensure that patients’ wishes are followed, without impacting on their direct care.