City of London Magistrates Court heard that on 12 November 2007, Howper 291 Ltd (formally known as Urang Ltd), were refurbishing a domestic mews property in Roland Way, South Kensington.

Lukasz Taborek, 23, from Acton in Ealing, was working on the first floor when it collapsed. He fell more than three metres to the floor below and falling materials then pinned him to the floor.

His right foot was completely crushed and veins and his calf muscles had to be surgically removed. His lower right leg was eventually amputated.

Urang Ltd were contracted to manage the refurbishment and assigned a project manager with no health and safety training.

The project manager visited the site for two hours every other day. She did not give the project the adequate supervision required and by her own admission was not trained in construction, nor was her manager experienced in construction.

The first floor was incorrectly built by subcontractors, who had left the site a month prior to the incident. Concerns regarding the general safety and tidiness on site had also been raised on more than one occasion by the architect.

HSE’s inspector Peter Collingwood said: “This incident was entirely preventable. Had there been adequate management and supervision of the site, this terrible incident could have been avoided.

“This highlights the need for competent supervision to be present on site, so that any significant risks can be managed and controlled effectively.”

Howper 291 Ltd, of New Kings Road, Hammersmith in London, pleaded guilty to breaching section 3(1) of the Health and Safety etc. at Work Act 1974 at the City of London Magistrates’ Court. They were fined £10,000 and ordered to pay costs of £4,172.