Lift engineer Kevin Dawson, 45, was helping with the construction of Terminal 5A at London Heathrow when he died on 27 October 2007.

Isleworth Crown Court heard that Dawson was working from a ladder within the pit of a lift shaft, into which he and other Schindler employees were installing three new lift cars.

As a colleague used one of the cars to fetch equipment from a higher level, a counterweight descended, crushing Dawson and causing fatal injuries.

An investigation by the Health and Safety Executive revealed the unfinished passenger lift was used to carry workers, tools and materials despite missing key safety-critical components.

HSE also found the company’s radio and telephone arrangements were ineffective, and workers routinely communicated by shouting up and down the lift shaft. This was potentially confusing while others were working in adjacent shafts.

And there was no evidence that Schindler had identified the risk of impact or crushing from moving lift parts, and therefore failed to plan, organise or supervise activity to control and prevent this risk.

Schindler pleaded guilty to safety breaches and was fined £300,000 fine and ordered to pay £169,970 in costs.

After the hearing HSE Principal Inspector Norman Macritchie said: “Kevin Dawson’s death is a wake-up call for all involved in the installation and maintenance of lifts. His death was entirely preventable, and we need to ensure that nobody else suffers the same fate.

“It is hard to overstate the potential for death or serious injury arising from moving machinery, electricity and working at height – all of which are everyday risks in this industry.

“Lift shafts by their very nature are confined and often poorly-lit places, where heavy components can move suddenly, silently and without warning.

“Due planning and extreme care must be taken at all times. It wasn’t on this occasion and a life was needlessly lost as a result.”