A widow told today how she found her eminent professor husband electrocuted by a wire which had become 'live' because of a central heating boiler fault at the Cotswold farmhouse they had just rented for their retirement.

Professor John Alliston, 70, was clutching the wire in his hand and his fingers were burnt when wife Karen arrived home to find him unconscious in the garden just days after they had moved into the recently renovated property, a Gloucester inquest was told.

The Royal Agriculture College professor, a dad of two, is believed to have been doing some gardening work, pruning a bush at the back of Manor Farm House, Coates, when he touched the live wire and collapsed.

A health and safety expert told the inquest that the boiler equipment had become live because of faulty immersion heater in the boiler.

This would have been prevented if two safety measures had been in place - a residual current device and earth bonding of all the metal equipment - to prevent electrocution. But neither system had been installed.

The wire was part of a safety release pipe which led out of the house from the oil fired boiler to prevent explosion if it overheated.

There is no currently no legislation in place requiring landlords to have electrical safety checks carried out on properties before renting them but that may soon change, the inquest was told.

In evidence, Mrs Alliston said she and her husband had viewed the house in Coates, in late 2016 and rented it from Bledisloe Holdings Ltd in May 2017. They moved in on May 26.

On June 8, the day of her husband's death, she had been to Marlborough to see her sister following the death of their brother in South Africa, she said.

When she drove back through the farmhouse gates she saw her husband's car there and assumed he had come home from work.

"I walked through the gate and I could see him lying in the garden. Sometimes you get tired and just lie down but I thought 'this isn't right.'

She said she ran for help and saw the gardener at the house opposite, who rang 999 for an ambulance.

"He then came over and turned off the electric in the house," she said. "I realised by then that John had burnt his hand.

Sadly, Professor Alliston could not be saved. A pathologist later gave cause of death as electrocution.

Mrs Alliston told the jury that before the tragedy happened she had once felt a 'static buzzing' from the kettle and taps in the kitchen but her husband had told her there was no problem.

They had also been an 'almighty banging and crashing' from the central heating system on another occasion and they had turned it off.

Mr Parker, the neighbouring gardener, told the jury "As I turned Mr Alliston over I got an electric shock myself. We then went into the house to find the electricity box and shut it off."

He then went to meet the air ambulance which landed nearby to take the professor to hospital, he said.

"When I first saw Mr Alliston he was holding a thin copper wire which had burnt into his hand," he added.

"The wire looked as though it was just holding a bush back against the wall but later I could see it went into the house through a hole in the wall."

Vicktoria Viniczai, who worked as a caretaker for house owner Bledisloe Holdings Ltd, said the farmhouse had not been lived in from 2013 until the Allistons moved in.

It had been painted and refurbished with new bathroom, kitchen and carpets prior to them arriving and was 'nice and clean.'

There had been no concerns about the electricity system in the house that she was aware of, she said.

Chartered surveyor Angus Harley of letting agents Knight Frank said the Allistons had told him when they viewed the house that there was water running down a wall in the garage and into an electrical socket.

He had told Mrs Viniczai to get it checked and she later assured him it had been due to leaves on the roof and they had been cleared.

There was no electrical safety check carried out on the house prior to letting and there was no legal requirement for there to be one, he said.

But a gas safety check was carried out, an extra smoke alarm was fitted and safety cleats were fitted on the blinds.

"It was inconceivable to me that the electrics would be in an unsafe condition in view of the renovation work that had been carried out in the property," he said.

Health and Safety inspector Kenneth Morton said "The wire Mr Alliston was holding was in fact a copper pipe from the oil central heating system - it was there to prevent blowback should the central heating system fail.

"It had become live at 230volts because of a fault in the water boiler in the house. The fault was only found after the incident."

He said that if there had been a residual current device installed and the metal had all been earth bonded the pipe and wire would never have become live and Mr Alliston would not have died.

"All metal parts entering a property should be bonded to the earth point in the installation," he said. "That had not been done in this case.

"Essentially, there were three separate faults here. The lack of RCD and earth bonding and the fault in the immersion heater. It is due to the combination of these faults that this has happened."

He said he believed that legislation would soon be changed as he has been on a working group commissioned by the government to look at the need for electrical testing in homes.

"We have been considering whether it should be a legal requirement to have mandatory inspections and testing of electrical systems in the private housing sector," he said.

"There was a press statement about this on the 12th April this year. I am now on another working group drafting legislation for mandatory testing."

The inquest continues.