Rail staff in Scotland are to be equipped with body cameras as part of a crackdown against passenger aggression.
ScotRail is looking at deploying 230 of the devices for its frontline workers to protect them from physical and verbal attacks. It follows a proposed national roll-out of the cameras by Police Scotland.
Privacy campaigners have warned that public bodies are increasingly using “intrusive surveillance” when the case for doing so has not been made.
The rail operator is seeking bidders to supply and maintain the cameras and the monitoring system over three years following a trial in 2015.
That was held in response to a rise in assaults on staff, which rail bosses maintain is an ongoing problem.
A ScotRail Alliance spokeswoman said: “These cameras will help to make the working environment as safe as possible for all staff and customers.
“We do not tolerate violence of any kind on the railway and will do everything to assist British Transport Police in investigating any incidents and these cameras are a tool to help us do so.”
ScotRail insisted the cameras would only be activated during anti-social behaviour incidents, adding that, while staff will be encouraged to wear them, their use will be optional and targeted in aggression hotspots.
Rail chiefs refused to reveal the value of the tender, but said costs will be offset in part by reducing sick leave.
Renate Samson, the chief executive of Big Brother Watch, claimed the roll-out of the devices by ScotRail “should be met with caution”.
She added: “Whilst many public bodies are deploying these intrusive surveillance tools in order to improve safety, the evidence to support their use remains uncertain.
“Staff wearing the technology must be trained to use the cameras correctly and must, without fail, ensure passengers are clear if they are being recorded.
“Research exists to show that attacks on staff can actually increase if the public are unclear when they are being filmed.”
Body-worn cameras have been used by police in the north-east for several years. Police Scotland chiefs, who hail the technology for its evidential value, are looking at a national roll-out.
Calum Steele, the Scottish Police Federation’s general secretary, agreed the cameras have many benefits, but has called for debate on their affordability.