Critics have lambasted the system's weak security measures and say it is at risk of breaching both the Data Protection Act and the European Convention of Human Rights.
The DoH maintains the system is legal. But it said it would be against the public interest to release the legal advice it received from Queen's Counsel, citing section 42 (1) of the Freedom of Information (FOI) Act.
Colin McDonald, FOI manager at the DoH, said in a letter to GP that disclosure would 'aid transparency'.
But he added: 'In this case we consider that there is a very strong public interest in maintaining (legal privilege) ... so that the interests of the NHS and of patients can be best protected.'
Dr Paul Thornton, a Warwickshire GP and campaigner for patient privacy, said the lack of transparency disturbed him. 'The DoH seems to be demanding greater privacy in its dealing with lawyers than it is willing to grant patients in their dealing with doctors,' he said.
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