Police were called at around 6am on Wednesday following a collision between the vehicles on the taxiway at the airport, which is Europe’s biggest, close to Terminal 5.
A yellow airside operations pick-up truck was one of the vehicles involved. They are often driven around the airfield at high speed by Heathrow staff carrying out such tasks as directing aircraft and inspecting the runways.
A BA spokeswoman said: “We are deeply saddened by this tragic incident and are offering our full care and support to his family and colleagues.”
A Heathrow spokeswoman said: “We can confirm that following a serious accident involving two vehicles on our airfield, an airport colleague has passed away.
“Our deepest condolences go to the family and friends affected by this accident. We will be fully cooperating with the police in the investigation which will follow.”
Another man is believed to have broken his shoulder, though his injuries are neither life-threatening nor life-changing.
At least 20 BA flights from Terminal 5 were delayed and passengers were ordered to leave an aircraft which was unable to take off because of the crash.
The airline apologised to passengers and said it was doing “all we can” to ensure delayed flights depart as soon as possible.
No arrests have been made and officers from the Met’s Serious Collision Investigation Unit are investigating.