PrintWeek understands that the minder was attempting to clear a jam when the inch button stuck in after being released, causing the cylinder to draw his hand onto a metal guide, which sliced into his index finger.

The accident took place between 3am and 4am last Friday (6 August) and, according to reports, the man was trapped for up to an hour before paramedics were able to free him and take him to hospital, where he had surgery to repair the damage to his finger.

PrintWeek understands that the failure of the inch button was the result of a significant volume of debris, including ink residue and paper dust, that had built up on and around the button, and that Manroland has not been implicated in the accident.

According to a source, the inch button was replaced immediately following the accident, as were several others on-site.

A spokesman for the Health and Safety Executive said: "We were informed of the incident, which took place at around 4am on Friday, and are in the process of deciding whether to take it any further."

Unite national officer Steve Sibbald added that the union would wait for the outcome of any investigation before deciding whether any further action was needed.

"If the company is found to be negligent then we will pursue them with vigour on behalf of our member to extract as much compensation as we can," he said.

Southernprint declined to comment on the incident.