Contending that patients in vegetative states or minimal conscious states differ from patients with a "downward trajectory," he said these patients' conditions "do not in themselves lead inevitably to death."
The Court of Protection ensured "independent scrutiny" of any application to remove care, according to Saunders. Under the old rules, implemented after a 1993 case, the court did not prevent clinically assisted nutrition and hydration from being removed in over 100 cases.
"It did this because it recognized the emotional and financial pressure that families and clinicians can fell under," he said.
Saunders' group, Care Not Killing, has cautioned that changes in legal protocols should take into account advances in treatment of severe brain injuries, in areas like brain cooling techniques, intracranial pressure monitoring and neurosurgery.
There are "real, demonstrable and significant uncertainties about diagnosis and prognosis" in such cases, Saunders said.
"These have increased rather than decreased in the last 20 years and this is why continued court oversight is necessary," he added.
Care Not Killing is a U.K.-based coalition of about 50 human rights and disability rights organizations, health care and palliative care groups and faith-based groups, plus thousands of individual supporters. It advocates for better palliative care and against any weakening or repeal of existing laws against euthanasia and assisted suicide.
BBC legal correspondent Clive Coleman said that some experts believe the current legal practice had resulted in "individuals spending longer on life support in a vegetative state than was necessary because hospitals have shied away from going to court due to the expense and bureaucracy involved."
Coleman said the ruling makes clear that courts don't need to be involved in these cases, if doctors and families agree to withdraw nutrition and hydration and it is in "the best interests of the patient."
"However, the judgement cuts across ethical and religious beliefs and will divide opinion," he continued. "Some will see it as compassionate and humane, others the removing of a vital legal safeguard for a highly vulnerable group."
Doctors have not needed court permission to withdraw other forms of life-sustaining treatment, such as life-saving dialysis.
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Saunders, however, warned of the pressures patients' families and doctors will face.
"Given the huge and growing financial pressure the health service is under is this really an additional pressure, no matter how subtle we want to put medical staff and administrators under," he said.
It costs about $131,000 per year to care for patients in vegetative or minimally conscious states. Encouraging most patients down this path could result in $3.1 billion in savings for the National Health Service, said Saunders.
The Court of Protection process also costs health authorities over $65,000 in legal fees for each appeal, BBC News reports.