Father of three Allen Smith, 58, sustained a collapsed lung, smashed pelvis and head injuries in the fall at Anerley Methodist Church in Penge,  SE London, on 25 October 2011.

Westminster Magistrates’ Court hear that Smith was part of a four-strong team from Nationwide Roofing and Cladding Ltd including the firm’s director.

The gang was replacing the church roof owing to a series of leaks. They were three-quarters of the way through the job when the incident happened.

Smith was standing on a lightweight staging board while grinding off bolts, working from the roof ridge down toward the gutter and sliding the asbestos cement sheets down to labourers to lift onto a forklift truck.

As the work went on, one of the labourers heard a loud bang and turned to see Smith had fallen through the roof opening to the hall floor below. A length of the staging board was also on the floor.

Smith was in hospital for two months, has had a subsequent operation on his lungs, will need a hip replacement and is likely to suffer long-term arthritis. He is unlikely to ever work again.

An HSE investigation showed the firm had failed to install sufficient safeguards to protect workers from falling or to mitigate the impact of a fall if one happened.

These could have included scaffolding around the elevations and underneath the working area, and a safe working platform able to support the weight of workers fitted with guard rails.

Nationwide Roofing and Cladding of Fair Oak, Eastleigh, Hampshire, was fined £8,600 and ordered to pay £11,280 in costs after admitting a breach of safety regulations.

After the case, HSE Inspector Wendy Garnett said: “Mr Smith suffered life-threatening injuries in this fall and will have to live with the disabling consequences.

“However, his fall could have been avoided had Nationwide Roofing followed standard industry practice.

“The firm should have been fully aware of its duties and responsibilities to the labourers before starting the roof replacement works.

“But Nationwide neglected to put in place sufficient protective measures to guard against falls.

“This is not acceptable when you consider the devastating effects that a fall has on the lives of workers and their families.

“Firms of all sizes need to be aware of their duties to identify the risks of working at height and to take action to manage those risks.”