The four men working for Milbank Concrete Products, who do not wish to be named, suffered injuries including bruising, a dislocated shoulder, a fractured right arm and a twisted ankle.

Colchester Magistrates’ Court heard that the employees were working on a new precast concrete staircase and standing on a supporting frame – known as a ‘ski-slope’.

As concrete was being poured into the mould to create the stairs, five props supporting the ski-slope collapsed, causing the workers to fall from heights ranging from one metre to three metres.

The Earls Colne-based precast firm was fined £12,500 after pleading guilty to a single breach of safety laws.

HSE Inspector Keith Waller, said: “This incident could have been more serious.

“It could also have been easily prevented if it had been properly planned, assessed for risks, and sufficient training given.

“Having not carried out a proper risk assessment, Milbank Concrete Products therefore failed to have a safe system of work in place for the job and four workers were injured as a result.”