The HSE investigated after a 39-year-old member of staff, working at the Northern Tissue Group’s papermill in Lancaster, was injured when a walkway collapsed underneath him.

Lancaster Magistrates’ Court heard that the member of staff had been helping to hose down machinery, during a two-week shutdown at the factory, when he tried to cross a mezzanine floor six metres above the ground.

The metal grating gave way and the staff member, who wished to remain anonymous, fell partway through, hitting his arms and jaw on the floor and suffering bruising and friction burns.

A subsequent investigation found that there were no suitable inspection and maintenance regimes in place for checking the floor, despite it being at risk of rusting due to the humid environment.

NTG was fined £10,000 and asked to pay £5,866 in costs.

HSE Inspector Anthony Banks said: "The employee was lucky he was able to grab onto the mezzanine floor as he fell. If he had fallen all the way to the concrete below then he could have been killed.

"The incident happened in a very humid area of the factory and the company should have done more to make sure metal grates, which make up the walkway, didn’t become unsafe.

"Companies shouldn’t just wait for employees to be injured before taking any action to improve safety. It’s vital that proper maintenance systems are in place to protect workers."