An airport worker in his 70s was reportedly crushed to death by a 20 tonne high loading machine at Heathrow.
The worker was reportedly crushed by the 'scissor' machine as he worked a shift for cargo firm Dnata on the evening of February 23.
Colleagues were said to be distraught by the tragedy at Heathrow Terminal 3.
A police investigation is now underway to establish how the tragedy occurred.
The firm said it is co-operating with an investigation and also with Health and Safety Executive probe.
A Heathrow spokesperson said: "We can confirm that following a tragic accident 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 authorities as they investigate this incident."
A spokesperson for Dnata said: "We are deeply saddened to confirm that a Dnata colleague passed away whilst on duty at London Heathrow Airport.
"Dnata expresses its deepest condolences to our colleague’s family and is providing all possible support to them at this difficult time.
"We are fully co-operating with the authorities in their investigations into the incident.”
The Metropolitan Police have also been contacted for a comment.
Heathrow Airport is the world's fourth busiest airport and the largest in the UK.
It handles an average of 80 million passengers a year with London serving as the largest aviation hub in the world.
dnata is one of the world's largest air services providers offering ground handling, cargo, travel, and flight catering services across five continents.
British Airways is based at Heathrow, and this week saw mass cancellations after another major outage this weekend with passengers claiming their flights have been grounded at Heathrow.
The company's website has been completely inaccessible tonight, but they have said they are still operating flights and check-ins.
BA's check-in system was reportedly down in the second outage inside 10 days.