Aryn Stones Ltd had been contracted to build a new domestic property in Hampstead. On 31 May 2022, remedial works were being carried out on a partially built beam-and-block floor, when it collapsed, taking two of the workers down with it.

The two men – a welder, who is now 62, and a 31-year-old bricklayer – both sustained life-changing injuries, while two other men who were standing at ground level were injured by falling concrete.

Work on the build began in March 2021 but by February the following year, engineers who inspected the property identified errors with the connections of the structural steel beams. This prompted the remedial works that led the structure to collapse.

The failure happened  when the welder was using an oxyacetylene torch to cut a steel beam supporting the first floor while at the same time, another worker had been removing some Acrow props that were supporting the beam.

An HSE investigation found that Aryn Stones Ltd had failed to ensure the structure did not collapse while it was in a state of temporary weakness. The company also failed to put any measures in place to manage the temporary remedial work being carried out on the steel connections. They also failed to take all practicable steps to prevent danger to any person while the building was in a temporary state of weakness.

Aryn Stones Ltd, of London was found guilty of breaching safety regulations and was fined £50,000 and ordered to pay £39,000 costs following a two-day trial before City of London Magistrates’ Court.

After the hearing, HSE inspector Lucy Ellison-Dunn said: “Although two men were seriously injured, it was lucky nobody was killed.

“This was a completely avoidable incident had a system for the management of temporary works been in place. The company should have taken precautions to protect people from the risk of collapse.”