The aerial work platform toppled over from a yard next to the motorway near Heathrow.
The victim fell from the cherry picker cage as it crashed on to the M25.
He was pronounced dead at the scene on the hard shoulder.
The Genie Z-135 machine fell from a depot owned by Kimberly Access.
A statement from manufacturer Terex Aerial Work Platforms said: “Our foremost concern at this moment is for the accident victim’s grieving family.
“We express our deepest condolences to the family.
“Terex AWP has despatched technical experts to the scene and is working with experts to support the determination of the root cause of this tragic accident.
“We will also fully cooperate with authorities during their investigation to understand the cause of the accident.”
It is believed the victim was carrying out pre-delivery inspection checks on the cherry picker when it fell over.
To watch a BBC video of the stricken machine click here
The Genie Z-135
