When Andrew Castle's wife of 18 years asked him for a divorce, his response was to rig up a homemade electric chair in his garage and try to kill her.

After inviting Margaret Castle into the garage "for a chat", he sat her in the metal chair, intending to knock her unconscious with a rubber cosh before connecting the impromptu device to the mains.

However, his 61-year-old wife got up from the chair before he could carry out his plan and there was a struggle, during which she hit him several times with the cosh. She escaped through a side door, but the fight continued outside their bungalow in Knott End-on-Sea, Lancashire, before a passerby intervened and called the police.

Mrs Castle was treated for minor head injuries at the Royal Lancaster Infirmary. Her husband, also 61, was found in the back garden with self-inflicted knife wounds to his wrists after grabbing a blade from the kitchen.

He was sentenced to 10 years in prison by Preston crown court , having admitted attempted murder, at a hearing in May.

Officers who examined the garage found an electric cable running from a 13-amp plug with exposed wires. When switched on, the live and neutral wires which would have completed a circuit if touched together or put in contact with the chair.

Neighbours said the couple, who went on walking and cruising holidays together, appeared to be happy and content until March this year when she told him she wanted to end the marriage. One said: "We couldn't believe it when we heard what happened. We believe Andrew had, in effect, built his own electric chair to kill Margaret because she wanted a divorce. He managed to lure her into the garage on the pretext of them talking about it. He was about to do the deed but there was a struggle and she escaped."

Castle said he was "simply unable to cope" with the divorce and found it "overwhelming". A psychiatric report concluded that he had obsessive compulsive disorder and an adjustment disorder.

Detective Inspector Martin Clague, from Lancashire police, said: "It was a distressing case. He intended to kill his wife and had set plans in place to do this. It is rare for someone to attempt to kill their wife, or anyone, by these means.

"The fact Castle entered a guilty plea at least saves the family from having to go through the ordeal of listening to the evidence, which could have been very distressing for them."