Records failed to identify that a woman with mental health issues was at risk of self-harm and suicide when she was released from Harrogate Police Station.
In a new report, Her Majesty's Inspectorate of Prisons and HMIC also said a vulnerable 15-year old girl who was due to be monitored every 30 minutes was left for longer periods on several occasions, including one 55-minute gap between recorded observations.
After reviewing several custody records, inspectors found officers did not record all identified risks and vulnerabilities before release. The pre-release risk assessment for a vulnerable woman at Harrogate identified suicide and self-harm risks and mental health issues, but recorded that there were no threats of self-harm, no known issues and that she 'appeared in order', according to the document.
The report followed unannounced inspections in Harrogate, York, Northallerton and Scarborough, and noted the force had two fewer custody suites since the last review in 2010, following the closure of Selby and Skipton.
Martin Lomas, Deputy Chief Inspector of Prisons, said: “North Yorkshire Police had demonstrated some significant improvements in some areas since the last inspection, but more was required.
“Useful strategic oversight and some good work with partners was leading to some positive outcomes.
“While the report is critical of police cells being used as a place of safety, there is recognition of the progress made to date.
“Our main concerns relate to the treatment of detainees, with the disproportionate use of anti-rip clothing, inadequate oversight of the use of force and some risk-averse practices.”
The report praised North Yorkshire Police’s "notable progress in working with partners" to reduce how often a police cell was used as a place of safety for people with mental health issues. It also commended the use of mental health triage, which helped divert vulnerable people from custody, and recognised the “good efforts” of staff to try and ensure children got bail.
Custody sergeants were praised for refusing unnecessary detention, and interactions between staff and detainees were found to be “generally courteous”, although inspectors found the individual needs of some detainees were not always met.
Inspectors were also concerned to find that the use of anti-rip clothing was too often disproportionate to the apparent risk and officers needed to demonstrate greater understanding of the welfare of women in custody.
The report said: “The local authority out of hours appropriate adult service was inadequate for children and poor for vulnerable adults”, and there was only one forensic medical examiner covering the county, which led to significant delays.
It also criticised officers for not always recording the use of force and completed forms "lacked details to make any meaningful judgements".
Commenting on the report, North Yorkshire's Assistant Chief Constable Paul Kennedy, said: “We welcome this report from HMIC, and we will consider the recommendations very carefully.
"Custody can be a challenging and unpredictable environment, and officers often have to deal with difficult situations and extreme behaviour. However, we are fully committed to making sure that we only detain people when we absolutely need to do so, that everyone we admit to custody is treated with courtesy and respect, and that the highest standards of safety are maintained.
“The HMIC report is very clear that detainee care in North Yorkshire Police’s custody suites is good overall, but in the 30 cases that HMIC examined last August, they found there were still some individual cases where we can do better, and we will learn from that.”
Assistant Chief Con Kennedy said the force had already begun to make progress since the inspection was carried out, including using using CCTV to verify that the proper checks are being carried out on detainees at the proper time.
He said: “It is encouraging that HMIC has recognised the progress we have made in a number of areas. For example, we are using voluntary attendance interviews instead of custody where that is more appropriate, we have skilled healthcare professionals in place in our main custody suites, and we have places of safety available for those who have mental health problems and need specialist care. Nevertheless, we will keep making improvements.”
Police and Crime Commissioner Julia Mulligan said: "There is always more we can do and I will work with the chief constable to ensure services continue to improve. I was particularly disappointed to see the Appropriate Adult service for children and vulnerable adults was under-performing having raised this with the county council, the statutory provider."