PSNI has the UK's worst backlog on data analysis in child sex abuse probes
The PSNI has the worst backlog in the UK for analysing phones and computers in suspected child abuse cases.
Forces across the UK are grappling with lengthy backlogs of more than a year, according to new data.
A freedom of information (FOI) request sent to every UK police force by BBC Radio 5 Live Investigates revealed more than 1,800 cases were still waiting to be processed.
The BBC's results showed that, among the UK's regions, Northern Ireland had the oldest outstanding unallocated case dating back 18 months.
According to the FOI data, the longest delay recorded was for Wiltshire Police where a case was still awaiting forensic examination after one year, nine months and 19 days.
More than half of UK police forces reported delays of at least three months where cases were "waiting to be allocated" to a member of staff in the high-tech crime unit for analysis.
Five forces had devices which had not been examined after more than a year.
High-tech crime units are tasked with retrieving evidence from electronic devices in cases of suspected child sexual exploitation, with the information often key to securing convictions against paedophiles who use the internet to groom youngsters and go on to abuse their victims.
In June, the PSNI's cyber crime unit revealed it had viewed more than eight million photographs and video clips in one week in the search for sex offenders. The specialist unit has 21 officers.
In the last financial year, the PSNI examined approximately 6,000 mobile phones and 450 computers.
In September, 25 people were arrested in the first joint PSNI and National Crime Agency (NCA) swoop on those accessing online images of child abuse in Northern Ireland.
The operation had started in May when the nationwide crime fighting agency finally became fully operational here, almost two years after it began work in the rest of the UK.
The delay was down to a political row over how to make NCA officers subject to the same accountability mechanisms that regulate the PSNI.
In Wales, the oldest case, being dealt with by North Wales Police, dated back seven months.
Police Scotland's longest delay was 10 months.
One mother who contacted police over suspicions her daughter had been exposed to grooming attempts via chat rooms and webcams from the age of 13, said she was "shocked" to be told there would be a six-month delay in examining computer data.
Speaking anonymously, she told the BBC: "They wanted the laptop and her phone so we handed them over, and they did say 'we don't know how long it will take' because they had quite a backlog going back to January and this was July.
"I was shocked. My daughter was probably just one of many people they were talking to. These are children that need protecting."
She added that their case was accelerated by the police but only after her daughter took an overdose.