The patient from Priory Grange punched grandfather Edgar Brown, 78, breaking both his hearing aids and knocking his glasses to the ground. A hospital review said a thorough risk assessment had been carried out, that the patient had no history of violence and that there was nothing further staff could have done to prevent the attack on August 9. That has failed to satisfy the victim or his family, who feel the Howitts Lane hospital is failing to accept sufficient responsibility for allowing the patient to leave unaccompanied. Mr Brown, who walks with a stick, was sitting on a bench at Eynesbury green with his dog Millie when the man, on leave from the hospital, ran over to them. He had been sitting on the grass, making gestures, then he ran across to us, Mr Brown told The Hunts Post. He asked me why I was sitting in his seat, then came up to me and stood between my legs and started punching me in the head. Mr Brown, married to wife Patricia for 54 years, said the patient was a big chap in his 20s, and taller than him. The punches were coming in hard and fast on both sides and before I knew it I was almost unconscious, he said. I was saying to myself Youve got to stand up. I managed to do that, and he ran off. Mr Brown, an RAF veteran stationed at the Suez canal from 1951 to 1953, was left with injuries to his face and ear, but said the effects went beyond the physical pain. Every single night I wake up two or three times thinking about it, he said. I feel I let myself down. Im so cross with myself that I was unable to stop him. Police attended the incident, and confirmed Mr Brown had been punched multiple times to the head, which had caused bruising, dizziness and a small cut, but that a prosecution was not in the public interest. A hospital spokesman said a thorough investigation had been carried out, and stressed that the incident was extremely rare. She said: We have conveyed our deep regrets to Mr Brown and understand the distress caused to him by this isolated incident. The return to society of mental health patients at a certain point in their rehabilitation cycle is an absolute expectation from NHS commissioners but all unescorted leave is comprehensively risk-assessed by the clinical team at every stage. This patient had absolutely no history of violence towards other people and the hospital has an excellent safety record and a good and valued relationship with the local community. However Mr Browns son, Gavin Childs-Brown, believes those internal investigations into the incidents have been unsatisfactory, and said an offer to compensate Mr Brown for his broken hearing aids on the production of a receipt was disgusting. He said: Its the topic of my fathers conversation every day. He has lost six weeks of normal living. How do you provide a receipt for that?