Crane company Eurolift (Tower Cranes) has been fined GBP 50,000 for work accident which killed two of its employees.
The two men were carrying out work on a tower crane when another inexperienced worker was told to carry out a de-torquing procedure.
However, he had not been adequately trained and his actions caused the collapse of the crane.
The company was fined at Chichester Crown Court after being convicted of health and safety offences.
WD Bennett Plant and Services was also convicted in relation to the same incident and has been placed in administration.
Commenting on the incident, Health and Safety Executive (HSE) inspector Peter Collingwood said: " We would urge all employers to ensure employees are properly trained and understand the risks involved in the work they do."
Figures from the HSE revealed this week show there were 35 workplace fatalities in London and the south-east last year.