A COUPLE in their 70s, who spent more than five years waiting for their case to come to trial, have been cleared of any responsibility over the death of a self-employed gardener who was crushed while using their quad bike.

Former Ministry of Defence chief Nicholas Prest, 71, and his wife Anthea, 70, a former English National Ballet dancer, denied failing to discharge health and safety duties in connection with the April 2000 accident, which happened in a steep field they rented near their £2.5m Llandogo home.

Paul Marsden, 47, from Lydney, had taken the machine to go and spray nettles, but was found dead underneath the toppled-over Honda all-terrain vehicle three hours later.

Health and Safety Executive mechanical engineer David Whitton had told a Newport Crown Court jury that a "combination of factors" could have contributed to the quad bike being destabilised and rolling over – including a flat rear nearside tyre, the 20kg tank of weed killer and 15kg of other items being transported, no baffles or dividers to stop the liquid moving, and driver behaviour.

But quizzed by Keith Morton KC for the couple, he agreed the tyre was only inspected several weeks after the accident, the machine was in good condition, and there was "always a risk of an ATV turning over".

The jury was told that the driver had not been trained on using the vehicle, daily checks and tyre checks had not been carried out and he was not wearing a helmet.

But in statements to investigators, the couple said Mr Marsden, who had done work for them for more than six years, was "a very experienced rider", who had used it in woodland and on uneven terrain.

Mr Prest said he had "seen the skill he had", while the vehicle was in "good, serviceable condition" and "the most suitable equipment for the task".

Mr Marsden had been asked to spray nettles and briars in the nearby Summer Field, which the couple rented near their 15-acre Pilstone House, and had taken the Honda all-terrain vehicle with the tank of weed killer mounted on the back to save walking back and forth, the court heard.

But when he didn't return for lunch around 1.40pm, fellow contractor Nick Miles, who was cleaning the swimming pool, went to investigate and found his body beneath the quad bike.

A post-mortem later confirmed he had died of crush asphyxia.

The barrister for the couple, who have three children, told the court Mr Marsden had been working on a self-employed basis and therefore at his own risk.

Giving evidence, Mr Prest described the gardener's death as "a catastrophe", but it had been "tough" to be told in a "casual" manner by a police officer that they could face a manslaughter charge.

"We were deeply shocked. Traumatised is an overused word, but it was a ghastly experience,” he said.

Mrs Prest said it "would be like teaching granny to suck eggs" to have told Mr Marsden how to drive the ATV, and he drove it "frequently... and competently".

She also said he "took delight in seeing the flowers grow and was lovely to work with".