Philip Hames, of Weston-super-Mare, was working for Creagh Concrete Products on the University’s Claverton Down Campus when he adjusted a metal prop without realising it was securing a concrete plank above him.

The falling plank killed him instantly and narrowly missed a co-worker on November 1 2007.

Creagh Concrete Products Ltd of County Antrim was found guilty of a safety breach and was fined £100,000 and costs of £140,000 at Bristol Crown Court.

The court heard the positions and type of props used in supporting the concrete plank were critical, but placement was largely left to the workers to decide. One end of the concrete plank rested on an asymmetric steel beam on a movement joint.

Designs produced by Creagh Concrete Products failed to communicate to workers the nature of the expansion joint.

In adjusting the prop, Hames inadvertently destabilised the asymmetric beam the plank was resting on.

After the case, HSE Inspector Ian Smart, said: “Unfortunately there has been a rise in the number of fatalities caused by the collapse of structures under construction or refurbishment over the past few years.

“Mr Hames was an experienced carpenter but Creagh failed to recognise the scope of the work he was undertaking and failed to ensure he was made aware of how critical the placements of the props were and the fact they should not be adjusted.

“Therefore, Mr Hames would not have understood the outcome of his actions. It was foreseeable he and other workers on site would seek to move props and robust steps should have been taken to prevent this.

“Since this incident, the published standard for temporary works has been revised. It provides additional clarity on respect of the safeguards associated with the temporary support of structures. It is crucial that this guidance is followed by the construction industry.”