A highway maintenance worker apparently overwhelmed by fumes in the back of his van has been named as Ashley Mackie.

The 34-year-old installation engineer was discovered in a white Siemens Traffic Controls van which was parked at the junction of Greenford Road and Whitton Avenue West in Greenford last Friday afternoon.

Rescue workers smashed a side window to get inside but could not help the man, who was pronounced dead at the scene just after 12.30pm.

A post mortem examination suggests carbon monoxide fumes from an on-board generator could be responsible.

Police and ambulance were called just after midday to the busy junction just south of Sudbury Hill Tube, and heavy traffic built up while investigations were carried out. A recovery truck was brought in to move the van at around 4pm.

Recovery worker David Jenkins said: "I was told he was asleep in the back the van. It's just a tragic waste of life."

Mr Mackie, from Barnet, had been employed by Siemens for two years and was working on traffic light signals at the junction where he was found.

A Siemens spokeswoman said: "Our thoughts are with our employee's family. His colleagues at Siemens are also shocked and upset."

The incident is not being treated as suspicious.