Lee Byrne, 29 from Ince, was working on a project to replace the raised roof on the sports hall at Loreto High School in Chorlton with a flat roof when the incident happened on 9 November 2011.

Trafford Magistrates’ Court in Sale heard workers had removed old steel beams under part of the roof so that new beams could be installed.

This meant the corrugated tin panels on part of the structure were left unsupported.

Byrne was walking over the roof to his colleagues to get their lunch order when the panels under his feet gave way.

He fell ten metres, hitting a section of scaffolding on his way down to the ground.

He suffered a fractured pelvis, broken fingers and his right arm and elbow were smashed to pieces.

He has had to have an artificial elbow fitted and has so far been unable to return to work due to the extent of his injuries.

The court was told there was no barrier around the fragile section of the roof, and the scaffolding had only been erected under parts of the roof rather than covering the full width.

His employer K Pendlebury & Sons Ltd pleaded guilty to a breach of safety regulations and was fined £10,000 and ordered to pay £3,539 costs.

Speaking after the hearing, HSE Inspector Matt Greenly said: “The injuries the employee has suffered will affect him for the rest of his life but he could easily have been killed if he hadn’t hit the scaffolding on the way to the ground.

“I issued an immediate Prohibition Notice when I visited the site preventing anyone from working on the roof until safety measures had been put in place due to the risk of injury.

“The company had been removing a series of supporting steel beams but no barriers were put up to prevent access to the fragile roof panels despite the company recognising before the incident that barriers would be needed.

“There should also have been scaffolding under the whole of the roof to catch anyone who fell.

“This was a big project that should have been carefully planned but sadly the company’s failings have led to an employee being badly injured.”