On the 2nd January 2015 an investigation was commenced in the death of Joshua Knox-Hooke. The investigation concluded at the end of the Inquest on the 28th July 2016. The conclusion of the Inquest was a narrative conclusion:

Joshua Knox-Hooke was taken by ambulance to A & E at North Middlesex Hospital on the 1st December 2014. He had lacerated his neck and wrist and reported that he had wanted to kill himself. A & E staff were aware of the history of psychosis and recent drug use. Despite this presentation he was not kept within eyesight pending a psychiatric assessment. He left the hospital before a psychiatric assessment was carried out. He was not seen or heard from until 28th December 2014. On the 28th December 2014 he was found deceased partly immersed in the Banbury reservoir. He died as a result of drowning. There was a failure by A & E staff on the 1st December 2014 to comply with the policy in place to ensure that Mr Knox-Hooke should be kept within eyesight of staff at all times.

Joshua Knox-Hooke was a 22 year old man. He had no history of mental illness prior to 2014. In July 2014, he travelled to Thailand and whilst on his travels suffered an acute psychotic episode. He returned to the UK on the 17th October 2014 where the diagnosis of affective psychotic episode was made. He came under the care of the mental health services provided by Barnet, Enfield and Haringey Mental Health NHS Trust. He was compliant with his mental health care and attended appointments as required with psychiatrists, care co-ordinator and psychologist. He was also compliant with medication. On the evening of the 30th November 2014, Joshua left home and told his brother that he wanted to die. He returned at 05:30 on the 1st December 2014 and during the morning of the 1st December 2014 he used a kitchen knife to cut both sides of his neck and wrist. He was taken by ambulance to the North Middlesex Hospital A & E. He was triaged by a nurse who noted that he had smoked crack cocaine the previous night and on returning home had cut himself with a kitchen knife causing lacerations to both sides of his neck and wrist. The paramedic staff handed over that Mr Knox-Hooke suffered from psychosis. They also handed over that when asked he stated that he wanted to kill himself. Mr Knox-Hooke also responded to a question by A & E staff to confirm that he wanted to kill himself. Mr Knox-Hooke was taken to the mental health bay. The triage nurse later saw him walking towards the x-ray department / exit. She asked where he was going. He said that he wanted a drink of water and she escorted him back to the cubicle and provided a cup of water. No steps were taken to ensure that Joshua was kept within eyesight at all times. He was captured on CCTV leaving the hospital at 11:38. There is no evidence available to suggest that he was seen leaving the hospital by any member of staff. There is no evidence to suggest that he was encouraged to remain within the unit or to expedite the psychiatric assessment.