The government’s planned cuts to legal aid in clinical negligence cases could cost the NHS almost three times more than is saved by the Ministry of Justice, a report has claimed.

While official estimates predicted savings of £10.5m, knock-on costs of some £28.6m, mostly borne by the NHS, had not been accounted for, the report by King’s College London found.

Justice secretary Kenneth Clarke has said legal aid is facing an “existential crisis” and must be streamlined to survive.

It was “neither affordable nor sensible” to have a system that operated like the NHS by providing “for any need”, he said last month.

The report, commissioned by the Law Society, found that overall the reforms could lead to knock-on costs of more than £130m.

It said the proposed reforms, which have already been delayed for six months, would save just £100m, less than half predicted in the official impact assessment.

The report, which comes as the government’s Legal Aid, Sentencing and Punishment of Offenders Bill is expected to face fierce opposition in the Lords, said the reforms were “unlikely to make a significant contribution to reducing the fiscal deficit”.

It looked at three key areas of legal aid - clinical negligence, private family law, and social welfare.

It found that in clinical negligence cases, the Bill would “generate a net loss of approximately £18 million per annum for the government which would largely be borne by the NHS through the NHS Litigation Authority.”

Social welfare cases, such as those which relate to physical and mental health, would lead to knock-on costs of £35 million and private family law cases would lead to knock-on costs of £100m, set against a predicted £170m saving.