Patients are not being given clear enough information about what will happen to their personal health records under a new NHS data mining scheme, the Information Commissioner’s office has warned.

Information on the nation’s medical history will be held on a giant database called care.data, a move which NHS England says is a key priority.

The database will be controlled by a new body, the Health and Social Care Information Centre, starting in March.

Patients will be able to opt out of having their information shared but Dawn Monaghan, strategic liaison group manager from the Information Commissioner’s office, raised concerns about what people were being told about the changes.

She told BBC Radio 4’s Today programme: “At the moment, we don’t think it is clear enough on the website or in the information that has been sent out exactly what data is going to go and what is not going to go because what it says in the leaflet is that your personal confidential data, you can object to your personal confidential data leaving the GP’s surgery and we are not sure without further explanation on the website, very clear views, whether people will understand what that means.”

The central database will enable experts to assess diseases, examine new drugs on the market and identify infection outbreaks, health officials have said.

But concerns have been raised about the prospect of keeping all of the information in one place, with campaigners saying that it could lead to privacy problems and data breaches.

Patients who do not want their information to be shared need to contact their GP practice.

Tim Kelsey, NHS national director for patients and information, told the programme the information would not be “identifiable”.

“This data is stripped of all the identifiers so, for example, the name and address features nowhere on this data; postcode, numbers, the data is stripped of all the identifiers and in their place are substituted meaningless pseudonyms in order that this data can be linked with other data sets.

“Can I be categorical? No one who uses this data will know who you are.”