Officers in the Yorkshire police force at the centre of the Rotherham child sex abuse scandal spend a “great deal of time” trying to “disprove” the word of victims, according to the policing watchdog.

Just days after the scale of abuse was exposed in the town earlier this week, Her Majesty’s Inspectorate of Constabulary (HMIC) has hit out at an “unacceptable” culture within South Yorkshire Police’s public protection unit that shows “a disregard for victims”.

The report said an “investigate to record” process was particularly evident in the unit, which deals with rape, serious sexual assault, honour-based violence and domestic abuse. This means incidents are not recorded as crimes at first, but investigated to see whether a crime has been committed.

It added there was “a great deal of time spent trying to disprove the word of the victim from the outset”.

The report said: “This culture of dealing with reports of crime shows a disregard for victims and is unacceptable, it hides the true extent of the picture of crime from the force and is particularly concerning when the offences investigated by this unit are often of the most serious nature and victims are often the most vulnerable.”

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Following recent visits to the force and an examination of crime records from November 1 2012 to October 31 2013, inspectors found: “There is an inherent risk that a significant number of reported offences of a serious nature have not been recorded and that vulnerable victims have, as a consequence, been left unprotected or at risk of further offending.”

The fresh findings come as pressure mounts on South Yorkshire police and crime commissioner (PCC) Shaun Wright to step down in the wake of the Rotherham report, which found 1,400 children were sexually exploited between 1997 and 2013.

Mr Wright was elected as PCC in 2012 and was head of children’s services at Rotherham Borough Council between 2005 and 2010.

In his PCC manifesto, Mr Wright listed “Making sure victims and witnesses get a better deal” as one of his priorities.

He added: “ It’s crucial that we treat victims and witnesses with the respect, care and support they deserve.”

South Yorkshire Police was one of a number of forces criticised for under-recording crime, highlighting the impact this had on vulnerable children who had been victims of sexual assault.

Out of 152 incident records, inspectors found that 117 crimes should have been recorded – but 24% of them were not.

In addition, out of 53 reports referred from “other agencies” – such as social services – to the force’s specialist departments, 34 crimes should have been recorded but only 18 had been, meaning nearly half were being effectively ignored.

The report added: “This level of under-recorded crime is a significant cause of concern and is a matter of material and urgent importance, particularly as some of these relate to violence and sexual assault against vulnerable children.”

Speaking after the child sex abuse report emerged this week, South Yorkshire Police’s District Commander for Rotherham, Chief Superintendent Jason Harwin, said: “Firstly we offer a sincere and unreserved apology for both young people that have been victims and families where clearly we have let them down.

“The important bit is though the services in Rotherham now are different…the services are now fit for purpose and we are keeping young people safe.”

In response to the HMIC report, a South Yorkshire Police spokeswoman said: “The force has lessons to learn in the recording of crime data and we are actively working through and implementing the recommendations set out in the report.

“The inspection took place between October 2012 and October 2013 and the report recognises significant improvements since then.

“We note the inspector’s comment that no conclusions can be drawn from such a small sample and the report quotes an error margin of +/- 10 per cent.

“We recognise that systems need improving and there is a programme in place to do so, including IT and the force’s public protection unit stand-alone system.

“The report also highlights a number of areas of positive work by South Yorkshire Police.

“It found no evidence of performance pressures leading to failures in crime recording and recognises the leadership team promotes data integrity throughout the force.

“It is important to recognise that this report is about the recording of crime and not how we investigate crime.”

It emerged today that South Yorkshire Police currently have 173 “live” investigations into suspected child sexual exploitation (CSE), it emerged today.

The number includes 32 probes in Rotherham, a spokeswoman for the force said.

The town is at the centre of a devastating report that found 1,400 children were sexually exploited between 1997 and 2013.

Professor Alexis Jay’s report, which was published earlier this week, criticised police for not making a priority and “regarding many child victims with contempt”.

In the light of the report Rotherham district police commander Chief Superintendent Jason Harwin offered an “unreserved” apology to CSE victims.

The officer said that in the last 12 months in Rotherham 15 people have been prosecuted or charged with CSE-related offences.

South Yorkshire police received 157 reports concerning CSE last year in Rotherham, according to Prof Jay’s report.

It was said to be clear from interviews with serving police officers that tackling CSE “was now a priority” for the force.

The report said recent operations have targeted “suspect hotels and limousine companies”, while an inquiry was looking into “high-risk” missing children.

Chief Constable Simon Bailey, national policing lead for child abuse investigation, said awareness of CSE has “increased significantly” in recent years.

He said: “Protecting vulnerable people from abuse and exploitation is a priority for the police service. Chief constables across the country are investing significantly more time and resource in investigating allegations of child sexual exploitation and are dealing with an unprecedented increase in reports.

“In 2013 ACPO developed a national plan for tackling child sexual exploitation. This plan incorporates best practice, lessons learned from previous reviews and input from experts in the field.

“In a relatively short space of time, police forces have moved from child sexual exploitation being barely recognised and understood to making real progress in ensuring that their response is effective.

“Many of the recommendations in the action plan have already been achieved and the plan has been updated with further recommendations for improvement.

“All chief constables have committed to delivering this action plan.”

He said the findings of the report are “shocking”.

Mr Bailey went on: “Nothing can excuse the events it describes. We have made real changes in policing to stop this kind of abuse happening and to protect young people.

“Let me assure victims that if they report abuse to the police we will listen to them. We will take their allegations seriously. We will treat them sensitively.”