A Bristol motorway engineer working to replace a roadside CCTV camera died after he fell 16ft off the edge of the M5 and down an embankment, an inquest heard.

Cecil Grant, 42, from Southmead, died 10 days after plummeting off the edge of the hard shoulder down a steep drop as he worked in darkness on Tickenham Hill in January 2006.

The inquest at Flax Bourton heard that Mr Grant's bosses at subcontractor Serco had not warned him he would be working near an embankment so he didn't bring a safety harness.

And the jury was told the motorway was not properly lit for the work and Mr Grant was equipped only with a torch he had bought himself from a DIY shop for £10.

Mr Grant's colleague Peter Wilson, who was working with the father-of-two to replace the faulty camera, said he would never have volunteered to carry out the job if had he known about the risks.

He told the jury yesterday that he heard Mr Grant shout out before he "vanished" off the edge of the road on a split level section of the motorway northbound between junctions 19 and 20, for Portishead and Clevedon respectively.

Coroner Brian Whitehouse heard Mr Grant underwent surgery for a back injury he sustained in the fall and later died at Frenchay Hospital from a blood clot which developed because he had become immobile for several days.

Mr Wilson said: "There was a lot of shrubbery around and I didn't know there was a huge drop just inches away from me. I looked up and Cecil had vanished and I started to look for him. Then I saw his torch shining up from below.

"If I had known it was such a dangerous location, I wouldn't have gone to do the job."

The inquest heard that a warning sign was installed near the camera following the accident and a Highways Agency inspection recommended a guardrail be installed along the edge of the road.

Firefighter and paramedic Eric Pimm, who was lowered down to help Mr Grant after the fall, said he was aware of two other occasions when people had dropped over the edge of the motorway in the same area in the last eight years.

Paul Mitchell, head of health and safety at the Highways Agency, said the existing crash barrier, which was fixed a few feet from the drop, was effective in preventing people nearing the edge of the road and installing a further guardrail was not necessary.

Detective Inspector Ben Batley told the inquest the Crown Prosecution Service had considered charges of involuntary manslaughter against three employees of Serco but they were not pursued.

He said the investigation had since been passed to the Health and Safety Executive, which was yet to conclude its inquiry into the fall.

David Leckie, representing Serco, told the inquest his client had not been made aware of the steep embankment by the Highways Agency and other main contractors. The inquest continues.