SOARING use of smartphones and tablets is increasing pressure on police investigating pornographic offences, a senior officer has said.

Detective Chief Superintendent Simon Mason, North Yorkshire Police's head of crime, said demand on high-tech crime units was growing.

He was speaking after a man was convicted of possessing more than 11,000 indecent images, in a case that took four years.

Police raided the home of Ronald Douglas, in Wilton Rise, Holgate, in August 2010 but he has only now been sentenced.

Douglas, 51, was given a three-year community order with supervision and ordered to complete a sex offenders' treatment programme. He was also put on the sex offenders' register for five years.

Nick Adlington, prosecuting at York Crown Court, said so many people are being caught downloading sexual images of youngsters that police computer experts were overwhelmed with work.

It took them three and a half years to analyse the 40,000 pictures they found on Douglas's computer, iPad and storage devices. It then took police and the CPS ten more months to put a case together and charge him.

Douglas pleaded guilty in March 2014, to charges of possessing indecent images of children, possessing indecent videos of children, possessing prohibited images or children and possessing extreme pornography. His sentence was then delayed by another eight months because of his health difficulties.

DS Mason said after the case: “Due to the growing number of devices available to people who want to access indecent images on the internet, the demands placed on police high-tech crime units continues to grow as does our investment in this area.

“In this particular case I understand there were high volumes of media devices and exhibits that were seized which required detailed examination by North Yorkshire Police’s hi-tech crime unit. Only those exhibits and media devices found to contain illegal indecent images are the subject of court proceedings, but clearly all other material has to be considered."

“In parallel to this and any other existing hi-tech crime investigation is the need to constantly re-prioritise new cases which are referred to the unit to differentiate between possession of image offences and the severity of their content in comparison to a mix of technical and traditional investigative techniques that aim to identify people who commit hands-on abuse or create indecent images."

He said some cases could take longer than preferable, but said the force also had to ensure its investigations in a "very critical area" were thorough.

Referring to the time since the police raid, Judge Neil Davey QC told Douglas: "From that point on, you must have known what they would have found and you would one day be sentenced for it. It must have been a nerve-wracking time for you."

He said he was passing a non-custodial sentence because most of the images were low-level sexual images, because of the delay since the raid and because the public interest would be better served if Douglas could be taught that his interest in indecent images of children supported the sexual abuse of children to generate the photos he and others looked at.

Douglas's barrister Louise Reevell handed in reports from two psychiatrists and his GP.

"He is a complex character whom I respectfully submit needs intervention from the authorities," she said. Douglas had mental and physical health problems. "He has significant psychological issues and issues from childhood of a very sensitive nature."