The Health and Saftey Executive has closed a Willmott Dixon school site in West Sussex where two construction workers were killed in a crane accident last Friday

The men died when two 60 m cranes collapsed at the Highdown School site. The HSE has now closed the site while it investigates the circumstances.

The two victims were subcontractors working for Willmott Dixon. They were Gary Miles, 37, and Steven Boatman, 45, both from Reading, Berkshire. A third man sustained head injuries, and was this week in a stable condition at Worthing hospital, West Sussex.

It is understood the accident occurred as the cranes were being dismantled. As one crane fell it crashed into the other, which remained standing. The falling crane hit the roof of a building at nearby Durrington High School, but no pupils were hurt. The second crane was brought down in a controlled explosion after the HSE decided it could not be safely dismantled.

A Willmott Dixon spokesperson said the exact cause of death would not be known until after the investigation.

The HSE warned that a full report might take years to complete, prompting fears of a repeat of the Canary Wharf crane collapse inquiry, which has yet to be completed five years after the accident in Docklands.

This type of investigation can be slow as we need to seek advice from technical experts

HSE spokesperson

A spokesperson said: “The crane will be removed to our technical lab for full investigation once our on-site inquiries are complete. This type of investigation can be slow as we need to seek advice from technical experts.”

A source close to the HSE said that if the cranes were being dismantled while other workers not involved in the crane dismantling were on site, then the companies concerned had breached safety regulations.

Chief executive officer Rick Willmott said:“We are deeply saddened by this terrible event, and pass on heartfelt condolences to families and friends of the men.”