A paralysed patient has been left severely brain damaged after a nurse switched off his life support machine in an incident captured on CCTV. Violeta Aylward, an agency nurse working for the NHS, was caught on camera turning off the ventilator keeping quadriplegic Jamie Merrett alive.The 37-year-old, left paralysed from the neck down following a car accident in 2002, had a bedside camera set up at his home after becoming concerned about the standard of care he was receiving.Footage recorded only a few days after it was installed shows Miss Aylward fiddling with the ventilator before a high-pitched warning tone sounds, indicating it is switched off.Mr Merrett is then left fighting for life as the nurse panics about what to do next, unable to restart the ventilator or properly operate resuscitation equipment.It was not until 21 minutes later that paramedics who rushed to the scene managed to turn the life support machine back on.But by that time, Mr Merrett had suffered serious brain damage, which has left him with the mental capacity of a young child.Before the incident, he was able to talk, use a wheelchair and operate a computer using voice-activated technology.His family claims that the brain damage has severely diminished his quality of life, and he is now mounting legal action.Miss Aylward, who was caring for Mr Merrett at his home in Devizes, Wilts, has been suspended while the incident is investigated by the Nursing and Midwifery Council.Ambition 24hours, the agency which supplied her, said it could not comment as an internal investigation was ongoing.The NHS Wiltshire Primary Care Trust, which was responsible for providing care for Mr Merrett, said it was unable to comment due to pending legal action.Karren Reynolds, Mr Merrett’s sister, told the BBC’s Inside Out programme: "His life is completely changed. He doesn't have a life now."He has an existence but it's nowhere near what it was before. He is very brain damaged compared to what he was before.“He was a highly intelligent man and you could have long in-depth conversations with him and now it tends to be more simplistic."She added that her brother has become increasingly worried about alleged errors involving nurses operating his ventilator in the weeks before the incident.Mr Merrett had written to the trust by email, warning of his concerns but that nothing was done, she claimed.A confidential report by Wiltshire social services into the incident – leaked to Inside Out – concluded that the agency was fully aware it was required to supply a nurse with training in the use of a ventilator.The report says the company did not have adequate systems in place to check what training their staff had received.Mr Merrett’s solicitor, Seamus Edney, said: “In my experience, this is the worst case of negligence."No one has come forward to make any admission, so now almost two years after the event we are trying to get someone to admit liability for what has happened."In a statement, NHS Wiltshire Primary Care Trust said: "The PCT has investigated the incident in January 2009 when the patient’s ventilator care was compromised."We have apologised to the patient and his family for this, and have put in place a series of actions to ensure that such an event will not occur again either for this patient or others."The incident is the subject of likely litigation so the PCT is restricted in what further it may say in public."Miss Aylward, 55, from Reading, Berks, has not commented on the case.