Christian Concern is calling for an urgent inquiry after the Court of Protection ruled that a man who did not want to live with a stoma bag could be left to die.
The campaign group said the last wishes of the 34-year-old, named only as MSP in court papers, had been to receive treatment to live, despite the man writing a declaration refusing consent for life-saving treatment.
MSP was seriously ill with longstanding bowel problems and receiving treatment at Barnsley hospital.
He wrote an 'Advance Directive' in February stating that he did not want to live with a stoma - a hole created in the stomach to allow the extraction of digestive waste - and had his temporary bag removed on May 14.
Days later, he was rushed back to hospital with severe abdominal pain and sepsis. Christian Concern says it was at this point, when faced with the prospect of dying, that MSP changed his mind and agreed to have a stoma fitted during major surgery.
Following the surgery, MSP was sedated and placed in intensive care, with doctors saying he had a good chance of survival but would need a permanent stoma.
Barnsley hospital then made an urgent application to Mr Justice Hayden to determine whether that course of treatment was in MSP's best interests.
After hearing evidence at a virtual sitting of the Court of Protection, Justice Hayden determined that MSP had the right to refuse life-saving treatment. According to the Daily Mail, MSP has now died after life support treatment was withdrawn.
Christian Concern argues that the man's last wishes should have dictated the hospital's course of action and that MSP's Advance Directive was legally invalid because it was "not properly executed or witnessed".
Andrea Williams, chief executive of Christian Concern, said: "This case has come to the public's attention and on the face of the judgment serious questions are raised and need to be answered.
"When matters of life and death are at stake the system has to be transparent and subject to proper scrutiny."
She continued: "It cannot be right that the law can give a judge absolute power to seemingly enforce his own ideas of whether it is in a patient's best interest to live or die.
"This is made even worse when it is up to the same judge to say whether the patient lacks capacity to decide for himself. Taken together, this amounts to an unlimited power over anyone's life and death. This is compounded by the secretiveness of the Court of Protection and Family Division proceedings."
