Immediate action must be taken to improve South Yorkshire Police's approach to child sexual exploitation, the police crime and commissioner has said.
Shaun Wright commissioned a report into how the force provides protection to children and how it can be improved.
Between January 1 and September 30 police in Barnsley were involved with 55 child sexual exploitation referrals.
One high profile case was that of Anthony Marsh, 53, and Lee Davis, 39, who groomed vulnerable young boys on the internet - including boys from Barnsley.
They pleaded guilty to a string of offences including rape, sexual activity with a child, possessing and distributing indecent photographs of children and conspiracy to commit sexual activity with children and will be sentenced on December 2.
Mr Wright made child sexual exploitation a force priority and the report, by Her Majesty's Inspectorate of Constabulary, was published on Monday.
Until earlier this year, Barnsley did not have any staff dedicated to child sexual exploitation, but now has a detective constable.
The council decided it did not justify a dedicated social worker for child sexual exploitation. Social work support is instead provided by the district's wider child protection joint investigation team.
Although the whole force was found to have made 'considerable efforts' to improve, with 'pockets' of good and effective practice, the approach varied significantly across the four districts.
The report examined and made recommendations in 11 areas including leadership, strategies, management, training, structures, processes and intelligence gathering. It found leadership provided by the chief constable was 'unclear' to many police officers and staff.
Mr Wright said he was pleased the commitment and efforts of front line staff were recognised but said he was 'extremely disappointed' the force had failed to to put his plan into action. He said the chief constable must 'act immediately' to introduce the improvements.
Recommendations include reviewing the management of cases by staff in the dedicated child sexual exploitation teams and communicate and explain to the commissioner, staff and other parties the delay in deploying ten additional child sexual exploitation officers to districts.
