Martin McMenemy was working for O. Turner Insulation Ltd of Grimsby building a food processing plant in Ratby Lane, Leicester, on April 12 2008.

He was using a scissor lift to install wall and ceiling panels when he drove it unwittingly into a shallow uncovered pit in the floor.

The vehicle overturned and McMenemy was thrown out of it. He died later in hospital of head injuries.

A Health and Safety Executive investigation found that O. Turner Insulation Ltd and principal contractor Clegg Food Projects Ltd, of Nottingham, had failed to take simple precautions to cover the hole.

Leicester Crown Court heard the incident could have been prevented had the hole been covered with a metal plate or cordoned off.

O. Turner Insulation pleaded guilty to safety breaches and was fined £22,500 with £12,806 costs.

Clegg Food Projects Ltd, of Nottingham, also admitted breaching safety regulations and was fined £22,500 with £12,674 costs.

After the hearing HSE Inspector Stephen Farthing said: “This was an entirely preventable tragedy. A family has been left without a father because simple precautions were not taken to eliminate what was an obvious hazard.

“Both companies had a duty to plan, manage and monitor the work being carried out under their control, but failed in that duty.”

McMenemy had two sons, Ashley and Simon. His oldest son, Ashley worked with him as a thermal insulation engineer for a number of years, including at McMenemy’s own company and later O. Turner Insulation Ltd, but changed career after the incident.

He said: “I lost interest in working as a thermal insulation engineer following the incident. The work wasn’t the same and I simply didn’t enjoy it any more.

“I miss Dad and I am upset that if I ever have any children he will not get to see them. I often think of him, and all the things we haven’t yet done. I miss getting to know him better.”