Lewes Crown Court heard the company had been subcontracted to design and build the mechanical and electrical systems in a number of new buildings at Manor Royal Industrial Park in Crawley in January 2007.

A cable installer, who does not want to be named, was working in a scissor lift with two colleagues tying cables into overhead trays when the trays collapsed, knocking the man out of the lift and causing him to fall eight metres to the floor below.

The man, from Hartlepool, suffered severe spinal injuries and is now paralysed from the waist down.

The court heard that Skanska Rashleigh Weatherfoil Ltd had failed to ensure the safety of its employees while carrying out the installation of the cable tray systems.

The firm admitted safety breaches and was fined a total of £120,000 with full costs of £81,927.

After the hearing, HSE’s Inspector Denis Bodger said: “This tragic incident would have been avoided if the company had ensured all parts of the cable tray system had been properly designed and installed, including how it was attached to the building.

“During installation, when components were failing or showing signs of failure, Skanska took no action.

“When construction work is subcontracted, whether it’s design or installation work, it is essential companies have adequate systems in place to manage this effectively.

“The fine reflects the seriousness of the omissions by this company. Skanska Rashleigh Weatherfoil Ltd employed people to do highly hazardous work and yet failed to take the appropriate steps to ensure their safety.

“It is essential that employers consider all aspects of difficult and dangerous work; health and safety is not just a phrase, it is a considered approach to protecting people in the workplace”