An investigation into an explosion which nearly killed a workman in New Malden has concluded there should be no enforcement or prosecution.

A 24-year-old worker working on the collapsed sewer in Kingston Road was found lying on the floor in a critical condition on March 18 last year.

It later emerged he had been thrown to the ground by an electrical explosion from a generator.

Personal injury solicitors later said he had been blinded in one eye and had a metal plate in his broken left wrist, but had regained consciousness and left hospital.

A spokesman for the Health and Safety Executive (HSE) said today: “The HSE did investigate and there’s not going to be any enforcement action.

“The public can be reassured by the fact there isn’t a prosecution happening or any enforcement action.

“The HSE has done a full and thorough investigation and there wasn’t the requirement there for any enforcement action.”

He said he could not give any more details about what caused the explosion and said that, due to the number of investigations, the HSE did not release reports into non-enforcement incidents.

Bob Miller, of Fenton Solicitors, which is representing the injured man, said: “We want to find out more on what the HSE know. We want to find out how they got there.”

At one point, detectives from Kingston CID were involved, trying to find out how he sustained his head injuries, which left pools of blood around the work site.

The HSE was believed to be investigating a theory the generator, owned by Selwood and rented by Thames Water, may have been tampered with during the repair of a collapsed sewer.

Alternatively, gas may have leaked from underground pipe work.