Kidderminster Magistrates’ Court heard how the 48-year-old man, who does not want to be named, was rectifying a fault which had stopped a brick packaging line from moving at the firm’s Worcestershire factory in October 2009.

He entered the safety zone around the line, which was protected by a perimeter fence with interlocked access gates, and climbed up onto the conveyor belt to fix the problem.

But the line suddenly restarted, activating a pallet lifter which came down and crushed him.

He suffered a serious puncture wound to his back, cracked several ribs and sustained extensive bruising to his face and leg. He was off work for six weeks.

An HSE investigation found an interlock on one of the gates, which should have isolated the machinery, had been disconnected some days before the incident to allow a printer within the perimeter fence to be serviced.

The company had also failed to carry out an adequate assessment of the risks arising from working on the printer within the perimeter security fence and the controls required.

Speaking after the hearing, HSE inspector Chris Gregory said: “A man suffered potentially life-changing injuries following an incident that should never have happened.”

Wienerberger Ltd, of Brooks Drive, Cheadle Royal Business Park, Cheadle, Cheshire, pleaded guilty to breaching safety regulation and was fined a total of £20,000 and ordered to pay full costs of £11,611.