The three ceramic tilers, Michael Whateley, 28, his brother Robert Whateley, and Paul Keen were waiting in their car for the building site to be unlocked in Broughton Road in Banbury.

Plant operator Keith Payne was carrying out routine checks to a telehandler near the car on the January morning two years ago.

Payne climbed into the cab of the truck to lift and extend the unloaded boom. However, the truck tipped over and the forks at the end of the boom landed on the car, crushing the roof of the vehicle.

Michael Whateley died from his injuries. Robert Whateley suffered fractures to his spine, and a brain injury. Paul Keen suffered neck and spinal injuries, a broken ankle, broken ribs and a fractured breastbone.

The Health and Safety Executive said the incident would have been preventable if Payne had operated the machinery on level ground.

Instead, he extended the boom of the machine to its limits while it was not suitably positioned.

House builder Linden was also £7,500 and ordered to pay costs of £25,000 for failing to ensure the equipment was maintained properly and tyre pressures were found to be lower than recommended.

Following the hearing, HSE Inspector James Powell said: “This was a horrific accident that was totally avoidable.

“Construction sites have inherent risks, and even rough-terrain lift trucks have strict operational limits that need to be observed. With competent operation and suitable maintenance, tragedies like this should not happen.

“Lives have been destroyed here and today’s sentencing must serve to remind all employers and employees of their duties and responsibilities while using this type of machinery.”