A 16-year-old girl was taken to hospital after refusing food and water during 44 hours in police custody, an inspection report has revealed.

The "serious" incident was among several highlighted in a report by HM Inspectorate of Constabulary (HMIC) on standards of child protection within Nottinghamshire Police.

Conducted in September as part of an HMIC programme assessing child protection throughout England and Wales, the report said police staff responsible for managing child abuse investigations in Nottinghamshire were highly committed and dedicated to providing good outcomes for children.

But HMIC inspectors expressed concern at cases in which children were being unnecessarily detained in police custody overnight.

Giving details of "the most serious case" seen by inspectors, in which a 16-year-old was detained for 52 hours before being taken to hospital, the report said: "It was only after the girl had been in custody for 44 hours that custody staff realised that she had gone without food or water.

"She was subsequently treated by a paramedic before being taken to hospital.

"The force was fully aware of the circumstances of this case, which was subject to an independent health service review at the time of the inspection, but it was not clear to inspectors that steps had been taken to learn the lessons."

In a statement, Nottinghamshire Police said the girl, who was in custody under mental health laws for her own protection, had declined the offer of food and water on several occasions.

Assistant Chief Constable Steve Jupp said the force recognised that people in crisis due to mental health should not be in police custody.

Mr Jupp said: "We never want to be in a position where children need to be taken into custody, whether for crimes or because of mental health issues, and we continue to work with our partners to find alternative accommodation wherever possible.

"A full review into the case of the 16-year-old girl who was arrested has been conducted. Doctors and nurses assessed her welfare, and she was deemed to require specialist mental health assistance, and attempts were made over many hours to find appropriate accommodation."

HM Inspector of Constabulary Zoe Billingham said: "It is clear that that despite good work in many areas, Nottinghamshire Police needs to do more to improve its approach to protecting children.

"We found some areas of practice that are uniformly good, for example, the management of sex offenders.

"However there is often a lack of effective supervision of child protection investigations, which sometimes results in unacceptable delays and an inconsistent approach across the force.

"I encourage Nottinghamshire Police to act on our recommendations as a matter of urgency, and I have asked that within six weeks it provides me with an action plan to demonstrate how it will take forward our recommendations for improvement."