Ministers exercise rare right of veto to end 19-month campaign to let public see assessment of risks involved in NHS overhaul

The official assessment of the risks involved in the government's NHS shakeup will never be published after the cabinet exercised its rare right of veto to keep it secret.

The move ends a 19-month campaign by the Labour MP John Healey for publication of the Department of Health's own analysis of the damage its radical NHS overhaul may cause.

Healey, a former shadow health secretary, and an array of medical leaders argued during the stormy passage of the health and social care bill that MPs and peers needed to see the details in the transition risk register before they could consider the coalition's NHS plans properly.

Andrew Lansley, the health secretary, said ministers had taken the "exceptional" step of opting against disclosure – a tactic used only three times before in the previous decade – because releasing it would undermine the process of policy-making by reducing the quality of advice civil servants gave governments in future.

"This is not a step I have taken lightly. I am a firm believer in greater transparency and this government and this department have done far more than our predecessors in publishing information about the performance and results of our policies. But there also needs to be safe space where officials are able to give ministers full and frank advice in developing policies and programmes," Lansley said in a statement.

"The Freedom of Information Act always contemplated such a 'safe space' and I believe effective government requires it. That is why cabinet has today decided to veto the release of the department's transition risk register. Had we not taken this decision, it is highly likely that future sensitive risk registers would turn into anodyne documents, and be worded quite differently with civil servants worrying about how they sound to the public rather than giving ministers frank policy advice."

A spokesperson for the information commissioner, Christopher Graham, said he would need to be certain that the cabinet had followed rules that say the veto should be used only in cases meeting "exceptional" criteria for non-disclosure.

"We will need to study the secretary of state's statement of reasons for imposing the ministerial veto in this case. These must, under the criteria established by the government, be 'exceptional'. We will present the commissioner's formal report on the matter to parliament next week", the spokesperson said.

Healey condemned the veto as "a desperate act which will backfire badly. It is an admission of defeat on the legal arguments for public release. It is totally over the top to place NHS changes on the same footing as preparations for the Iraq war.

"There must be some very big risks in the government's NHS reorganisation for ministers to override the law with their political veto. "

The health department has lost two separate legal battles, both of which ended with it being ordered – first by the information commissioner and more recently by the first tier tribunal – to publish the register. It has decided not to pursue a further appeal, to the upper tier tribunal.

"The government has lost twice in law, yet still won't accept that patients and NHS staff have the right to know the risks ministers are running with the biggest ever NHS reorganisation", said Healey.

The British Medical Association, which represents the UK's doctors, expressed disappointment at the veto and said it remained vital for the risks inherent in the NHS reorganisation to be known. "There is still a huge amount of complex and very controversial secondary legislation to go through parliament in relation to the Health and Social Care Act, some of which will need to be voted through by MPs," it said.

"We are therefore disappointed that the government has decided not to publish the risk register in full. As we said well before the bill became an act, it's vital that everyone involved knows what the potential risks might be so decisions can be made based on a full understanding of what the impact might be."

The Department of Health said: "The … transition risk register from November 2010, which was a statement of potential risks of NHS changes, will not be published, following cabinet agreement and a final decision made by the secretary of state for health.

"The secretary of state sought the cabinet's views on the exercise of the ministerial veto in relation to the information tribunal's ruling that the transition risk register should be released. He did so as part of a full commitment to act in accordance with the provisions of the Freedom of Information Act, which makes specific provision for the exercise of such a veto."

Lansley added: "The choice to use the veto rather than appeal the decision to publish the risk register was made because the secretary of state and the cabinet views this as an exceptional case where there is a fundamental disagreement on where the public interest lies in relation to the disclosure of the risk register.

"The upper tier tribunal would focus on points of law arising out of the first tier tribunal decision rather than the balance of the public interest on the evidence."

The shadow health secretary, Andy Burnham, said: "This disgraceful decision is a cover-up of epic proportions." He accused the cabinet of showing "flagrant disregard for the law of the land. David Cameron is desperate to keep the NHS risk register secret because he knows that, if people could see the scale of the risks he is taking with the NHS, they would not forgive him."

Dr Peter Carter, chief executive of the Royal College of Nursing, said the public interest meant the document should be published. "We believe it is wrong that yet again the government is refusing to publish, in full, the risks associated with these reforms. Today's decision is astonishing and means that the public are only being presented with a partial picture of the NHS reforms."

The only potential challenge to the veto would be if Healey or Graham sought a judicial review of the veto. But Healey said he thought the grounds for seeking such a review were "narrow to negligible". Department of Health sources said the veto marked "pretty much the endgame, the end of the line" of the long-running saga.