Dog walkers warned a power company to cut the electricity to a fallen cable 20 minutes before a runner was electrocuted and killed, an inquest has heard.

Dr James Kew, 41, of Ashdon, died after running into a power cable at neck height on July 24, 2012, jurors at Chelmsford Coroner’s Court were told today (Monday).

It emerged that a couple, who lived in Newport, were walking their dogs when they discovered the cable near a footpath in Ringers Farm, at about 8pm.

Dr Kew, a member of Saffron Striders, was out with a group of two other runners when he came into contact with the 11,000 volt cable at about 8.40pm.

His death would have been instantaneous, a pathologist told jurors. Dr Olaf Biedrzycki added that the cause of death was high voltage electrocution.

Roger Musgrove and his wife Karen tried to raise the alarm about the impending danger of the cable at 8.13pm.

Mrs Musgrove Googled National Grid and her husband made the call on her phone. She received a phone call back from UK Power Networks at about 8.19pm and Mr Musgrove answered. He explained the situation to the company before asking for the power be cut, the inquest heard.

Mr Musgrove’s fear was that a cyclist may ride long the path and come into contact with the cable.

Ian Henley, also a member of the Striders running club, told of the moment he witnessed Dr Kew’s death. He was running just behind when he described seeing Dr Kew stop suddenly and, after trying not to run into the back of him, said Dr Kew was “lying stiff on the floor”.

Mr Henley reported feeling a shock when Dr Kew was electrocuted and another “big shock” when he grabbed Dr Kew’s trainer to try and pull him off the electricity cable.

He and another runner went off to get help by flagging down passing motorists on Debden Road.

Mr Musgrove, who said he and his wife left the scene about 10 minutes after reporting the cable fault, described hearing a crackling noise “like a firework” at about 8.40pm. He returned to find part of the corn field alight, describing it as a “huge fireball”. Mr Musgrove told the court: “Two people shouted ‘Look there is someone in there’ and my wife called 999 again.”

He said he saw Dr Kew lying face down with his head touching the power cable, before shouting at someone: “It is too late, they are dead.”

Another walker, Charlotte Wilson, had discovered the cable hanging down earlier in the evening at about 6pm. She described the field where the footpath ran through as being “a wall of yellow crop higher than waist height”.

Ms Wilson told the court the cable was “suddenly there” in front of her as she made her way in the direction of Debden Road.

“I recall it being lower than eyesight but it couldn’t have been too low because it didn’t take much to duck underneath it,” she said.

“It looked like an elastic band that had lost its elasticity. There was no noise so I assumed it wasn’t live. From what I now know it was very dangerous but I didn’t know that at the time.

“If I had known I would have turned back the other way.”

Ms Wilson’s intention was to report the hanging cable to the authorities but she “became embroiled in other things” when she got home and heard about Dr Kew’s death the next morning.

Mr Musgrove also described how he had tried to “build a barrier” on the footpath to warn people about the cable. He made a “pyramid of sticks” and placed a wooden sign where the footpath entered the field.

The inquest continues.