West Midlands police have defended their decision to use volunteers for forensics work that would involve viewing indecent and distressing images after being warned that it was “a disaster waiting to happen”.

The force was criticised after advertising unpaid roles in its digital forensics team, with an advert that warned volunteers would “routinely come across distressing imagery including indecent images, fatal road traffic accidents, live CCTV footage recovery of incidents”.

The force said it was looking for people to commit at least 16 hours a month to the role and said that a criminal record was not a barrier to volunteering.

Michelle Painter, the assistant director of forensic services at West Midlands police, said: “Volunteers present us with a fantastic opportunity. We have the opportunity to use highly skilled individuals, who are experts outside of policing, but with the necessary experience and expertise to help our investigations.

“Equally, the volunteers themselves are developing their experience and using their skills to help others and bring more people to justice.”

Writing on Twitter after the advert was first posted, digital forensics expert Sam Raincock said: “I actually cannot believe what I have read here. West Midlands police wanting digital forensic volunteers and for them to sit and view indecent images of children! It is an absolute disgrace and a disaster waiting to happen!”

She said her immediate concern was welfare. “Working in digital forensics in the criminal sector is difficult. You will see things you have no idea how you will react to, regardless of who you are and what you think you can cope with. Sadly some of the material ends careers.”

Raincock expressed concern that volunteers would not receive sufficient support if they found themselves deeply affected by the images they saw. She wondered if volunteers would get paid by their regular work if they needed time off for counselling.

Speaking to the BBC, Stuart Richards, who teaches cyber-forensics at the University of Gloucestershire, said someone would need to be given counselling before carrying out such a role, and would ideally have a psychological evaluation every three months.

“You’ve got to be a very strong individual to be able to deal with it,” he said. “I don’t think you can give someone the support they need in that sort of environment in that sort of time frame.”

Painter acknowledged that the roles would “not be for everyone”, but said the force needed volunteers with digital expertise outside of policing to support its investigations. “Volunteers have not replaced staff, there has been no reduction in staffing numbers since their introduction,” she said.

“Their welfare is an important consideration and is reflected in the age restriction and the recruitment process. Occasionally, some investigations do have an element of investigating indecent images but that is not the only aspect of the digital forensics service.”

She said that the support available to staff would also be available to volunteers, including six-monthly clinical supervision appointments. “We appreciate that this line of work is not for everyone, which is why we are explicit around the potential exposure to indecent and distressing imagery,” she said.