Reading Crown Court heard that, on 13 May 2014, Ben Wylie was assisting Ruislip Plant Director Noel Kearney (since deceased) with the maintenance of a high-pressure grease track adjusting mechanism at a construction site in Maidenhead.

During the process, the grease nipple assembly and a stream of high-pressure grease was forcibly ejected from the mechanism and struck Wylie in the shoulder and chest causing fatal injuries.

An HSE investigation found that the components had been forcibly ejected on the previous day and had sustained damage in that event, reducing the pressure at which it would subsequently fail.

Once the fitting had been ejected, it should not have been refitted.

Despite the fittings having been previously ejected and damaged, Kearney attempted to modify and refit the grease nipple and adaptor to the high-pressure system. He then began to re-pressurise the tracks by pumping in grease using a hand operated grease gun.

The pressure built in the system and at a critical point the damaged and modified components were again ejected.

A pressure test with all suitable safeguards was required in these circumstances but there was no safe system of work during which resulted in the modifications to the grease gun bringing Wylie into the danger zone.

Ruislip Plant Ltd of Ruislip, Middlesex pleaded guilty to safety breaches and was fined £99,000 and ordered to pay costs of £116, 973.36.

After the hearing, HSE inspector John Glynn said: “HSE guidance is very specific on how this work should be undertaken and previously ejected or damaged parts must not be reused as they were in this case.

“This incident could have been avoided if Ruislip Plant Ltd had instead undertaken a risk assessment and devised a safe system of work.

“That safe system of work would necessarily have ensured that new parts were used, and that the safety procedure of a pressure test was performed. However, a new component was not used in this incident and the safety procedure was not adhered to.

“That failure to adhere to the correct procedure for pressure testing was directly causative of this incident. No control measures were put in place by Ruislip Plant Limited and that sadly led to the death of Ben Wylie.”

Wylie’s family were supported by campaign group Families Against Corporate Killers (FACK).

His mother Mylene Bensley said: “Ben’s death was not immediate, and I will have the visions of my son standing up after being shot by oil and a piece of equipment and stumbling across a building site saying he felt sick and spewing out blood and then falling down forever etched into my mind, due to the inadequate provision for his safety.

“The information started coming through in graphic minutiae of detail of how Ben died. I took each blow of information because my son had taken the blow that killed him, and I wanted to be there in my mind in any way I could be because I couldn’t be there for his dying moments.

“Ben’s body was returned home on my birthday in a coffin.

“We have suffered for seven years with no government assistance and we have to continue despite anger, deep hurt and insecurity.

“I am so grateful that FACK were so helpful because without their help and support this whole horrible experience would have been so much worse.”