A man has been found guilty of manslaughter by gross negligence after a woman walking past a construction site in Westminster died when three window frames weighing more than half a ton fell on her.

Lawyer Amanda Telfer, 43, was crushed to death on August 30 2012 when three large unsecured frames toppled over as she walked along Hanover Square in Mayfair.

Charges were brought against four individuals and three companies following an investigation by the Met Police’s Homicide and Major Crime Command and the Health & Safety Executive, and following a trial , 64-year-old Kelvin Adsett was convicted at the Old Bailey on Thursday (March 23) of manslaughter by gross negligence and offences contrary to Section 7a of the Health and Safety at Work Act.

Damian Lakin-Hall, 50, from Portsmouth Road in Cobham, was convicted of offences contrary to Section 7a of the Health and Safety at Work Act but acquitted of manslaughter.

The company IS Europe Ltd of Slough, Berkshire, was convicted of offences under Section 2 and 3 of the Health and Safety at Work Act.

Adsett, from New Road, Slough, and Lakin-Hall, 50, have been bailed to appear at the same court for sentencing on May 5.

Ms Telfer, a freelance intellectual property and media lawyer, was walking along the pavement past a construction site at 11.30am when three large unglazed window frames, together weighing 655kg, fell on her.

She died at the scene from massive crush injuries.

The window frames - one around 3.2m square and two approximately 3.3m x 1.8m - had been delivered the previous day as scheduled but could not be fitted immediately due to other delays on site.

They were left on the pavement overnight, leaning against the building. No efforts were made to secure them and no barrier placed around them.

No checks were made

No checks were made on them when the individual defendants arrived on site the next morning.

As the victim walked past, it is believed a door in the building blew open in the wind, hitting the frames and causing them to topple.

A worker inside tried to grab them but they fell, crushing Ms Telfer underneath.

Several members of the public came to help and together they managed to lift the frames off Ms Telfer. However, she was unconscious and not breathing.

Police, the ambulance crew and London’s Air Ambulance attended but she was pronounced dead at 11.57am.

Lakin-Hall told officers at the scene the frames had been secured to the wall with a ratchet strap, evidence showed that had never been the case.

'Laissez-faire attitude'

Detective Chief Inspector Andrew Chalmers said: “The individuals and company who were convicted in this tragic case had a laissez-faire attitude to health and safety and did not take their obligations seriously.

“Each had a responsibility for the safety of the construction site but failed to deal with a basic task that very obviously then presented a serious hazard.

'Her death was completely avoidable'

“Amanda died four-and-a-half years ago and this has been an incredibly long and complex case to bring before the courts with many many hours of enquiries carried out by my team.

“Her death was completely avoidable and it is satisfying for all involved in this case - and especially Amanda’s family - that the jury have convicted these people and companies today.”

Claire Gordon, 36, from Ashby Crescent, Leeds, and Steve Rogers, 62, of Sheering Mill Lane, Sawbridgeworth, Hertfordshire were acquitted of all charges.

Westgreen Construction Ltd of Richmond in Surrey and Drawn Metal Ltd of Leeds, West Yorkshire, were also cleared of charges.

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