Over 900 digital devices waiting to be examined by Hertfordshire Police
Five police forces in the East of England provided figures
Hertfordshire Police has a backlog of over 900 digital devices waiting to be examined by investigators, according to new figures from The Police Federation of England and Wales.
The Federation said officers are "overwhelmed" by the amount of digital evidence they are faced with, warning that mounting workloads are a result of forces struggling to attract new detectives.
Data provided to the Press Association news agency through a freedom of information request showed a total of 915 devices were awaiting examination by Hertfordshire investigators.
Across England and Wales, a total of 12,122 devices were awaiting examination. The figures, covering 32 police forces, were obtained by PA in February and March.
Although there is no local breakdown of what devices are being held, the most common items nationally include computers, tablets and phones.
These can be used to check messages, photographs, emails or social media accounts as part of an investigation.
Hertfordshire Constabulary was one of five police forces in the East of England to provide figures – at least 1,660 devices are waiting to be examined by all of these forces.
Estimates for how long it would take to clear the backlog for the forces that could provide one ranged anywhere between three months to more than a year.
A spokesperson for Hertfordshire Police said: "Hertfordshire Constabulary values the importance of digital evidence and our officers work hard to examine such evidence as quickly as possible.
"Reviewing and extracting evidence is an extensive process that must be done thoroughly and this can take some time.
"We are always looking for ways to improve our service and we are confident that the new Forensic Capability Network will help to reduce the number of digital devices waiting to be examined.
"We have also recently invested in this area with a further three Digital Investigators recruited to support this important work."
Simon Kempton, technology lead for the Police Federation of England and Wales, said: "Investigators are overwhelmed with the sheer volume of digital evidence.
"Forces are struggling to attract new detectives which is resulting in mounting workloads.
"There is also a need for forces to invest in technology which can help speed up this process by extracting and sorting this data automatically."
A study by civil liberties group Big Brother Watch in 2017 found that 93% of police forces in the UK extract data from digital devices seized as evidence from suspects, victims and witnesses.
The latest figures provided to PA show the devices are linked to a wide variety of crimes, including possessing indecent images of children, violent crimes, sexual offences, fraud and robbery.
Mr Kempton said the 43 forces in England and Wales have different approaches, with some using the latest technology to download and analyse data and others not.
A new Forensic Capability Network (FCN) was launched on April 1 to create a more unified approach between police forces.
National Police Chiefs' Council lead for digital forensics, Deputy Chief Constable Nick Baker, said it would help reduce the size of the backlog.
"The process of identifying reasonable lines of inquiry, extracting relevant material from devices and reviewing it is time-consuming,” he added.
"With the launch of the FCN and ongoing efforts to identify smarter working practices, we aim to see a reduction in the number of devices to be investigated at any one time."