The government is proceeding with the creation of a central store of data from GP records in England next month, despite the NHS suggestions a delay.
The data is moving to a central NHS Digital database , with the department of health saying it expects GPs to introduce the system from 1 July.
The NHS wanted a delay until September so patient had more time to learn about the system, the BBC has learned.
Critics worry the data could be misused by third parties.
Under a new system , called General Practice Data for Planning and Research , data from surgeries in England will be added to an NHS Digital database in ” near real time”.
The program will also extract data from record created up to 10 years ago.
Patients have until 23 June to opt out.
There is widespread agreement that the data could be of great value to research , but doctors are concerned the public is not well enough informed about what is happening.
The letter calls for NHS Digital to take immediate action to run a public information campaign”.
Some Gaps in east london have reportedly already refused to hand over patient data,
Citing the lack of an effective information campaign to tell the public about the changes.
Whether to delay , and in what form, has been the subject of intense discussion this week.
But on Thursday night , the Department of Health said in a statement that it expected the system to start on 1 July .it added that the plan would ” provide benifit to patients across England ” and that it was putting support in place.
Campaigning law group Foxglove is supporting a coalition of organization to challenge the scheme in court , and has sent a pre- action letter to the Department of Health and NHS Digital.
The warns that unless the government pauses the scheme and seeks ” meaningful patient consent” , the group will seek an injunction to halt it.
As a part of care data every household in England was sent a leaflet about the Programme and the possibility of opting out , although a survey by the BBC suggested that less than a third recalled getting one.