A prestigious north Cumbrian property firm has been fined £55,000 after a worker plunged through a roof, suffering horrendous injuries.

David Gill suffered a punctured lung and 17 bone fractures when he fell more than 25 feet through a fragile skylight and on to a metal conveyor belt in a building at Kingmoor Park, north of Carlisle.

Despite being so badly injured, he dragged himself to a fire door because the building was locked and his son was desperately trying get inside to help him.

At the city's crown court yesterday, the firm's chief executive Ross Nicholson looked on as a QC entered a guilty plea on behalf of Kingmoor Park Properties to a breach of health and safety law.

Adrian Farrow, prosecuting, said the firm employed Mr Gill, in his fifties, with his son – also called David - to look after routine maintenance on the Kingmoor Park estate.

Their routine duties included littler picking, unblocking gullies, and non-specialist roof work such as fixing leaks, typically two or three times a month.

If a roof repair was major, they would call in specialist contractors, said the barrister.

Mr Farrow said the firm's health and safety manual included a general risk assessment for the cherry-picker device the men used when working at height, but this was not brought to their attention.

“It's accepted that there was no risk assessment," said the barrister, "and no safe system of work devised to address the risks of working at height.”

He said neither Mr Gill nor his son had been given any training for roof work by their employer, although they were given a day's training with the cherry picker.

On the day of the accident, on April 8, 2014, Mr Gill and his son first used the cherry picker to do some routine maintenance, patching leaks in a building known as D2. They then looked at another possible roof job.

They decided they needed to bring in a roof specialist, the court heard, but went back to the roof so Mr Gill senior could retrieve some tools.

“Mr Gill [senior] stepped out of the basket and on to the roof,” said Mr Farrow. “It gave way beneath him and he fell into the building.”

At the time, Mr Gill was not strapped into the cherry-picker basket. He fell 5.5m on to a metal conveyor belt.

The barrister said: “The door to the building was locked, and Mr Gill's son attempted unsuccessfully to break into the building with a hammer. It was Mr Gill senior who managed to crawl to the fire door to open it from the inside.”

Mr Gill was then flown by air ambulance to hospital.

He later recalled hearing the ominous crack of the roof light as it was giving way. He spent a week in hospital, and was off work for three months. In the first days after his release from hospital it took him an hour to get out of bed and get washed.

His son was traumatised, waking up at night as he relived seeing his father fall through the roof into the building . Neither men was given any specific training for the task of working on a fragile roof, said the barrister.

Domonic Kay QC, for Kingmoor Park Properties, said the firm was decent and reputable and had a hitherto unblemished record. He said the firm's response to the accident had been exemplary.

It had quickly settled a civil claim, compensating Mr Gill, given him full pay while he was away from work, and fully supported his son and wife.

There were no systematic health and safety failing and the two maintenance men had used working at height equipment in their previous work.

“It's not as if they were not provided with personal equipment,” said the QC. “They had all the equipment with them which would have allowed them to do this work safely. They were both aware that these roof lights were fragile."

“It's not a case of someone being sent unknowingly in to the area.”

The firm also employed a health and safety contractor.

“This is not a roofing company,” added Mr Kay, repeating that it was accepted the firm did not give the men specific working at height training.

Passing sentence, Judge Peter Davies said no netting or fall prevention equipment was provided and the firm had simply relied on the two maintenance men to devise their own system of work.

But the firm had remedied their defective system and treated Mr Gill well; and nor did they have a history of health and safety blemishes.

As well as fining the firm, the judge ordered that Kingmoor Park Properties should also pay prosecution costs of £8,599.

After the case, the firm issued statement saying: “Kingmoor Park Properties Ltd deeply regrets the accident to David Gill on the April 8, 2014 . [It] The accident has been deeply felt by all in the company.

“Prior to the accident, the company had a good health and safety record.

“The company takes health and safety seriously and had no prior enforcement action in its 17 years of trading.

"The safety of its employees has always been a matter of paramount importance and it had not appreciated at the time of the accident that its documented work procedures were not sufficient."

“Consequently, the Company has pleaded guilty to breaching Section 2(1) of the Health and Safety At Work etc., Act 1974.”