A devoted husband entered into a suicide pact in which his wife died to end her ''awful'' suffering from a long-term illness, an inquest has heard.

Kenneth Brown had become the primary carer for his wife, Helen, who had been suffering from a long-term depressive illness when he agreed to commit suicide with her in order to help her end her pain and unhappiness which had left her housebound and reliant on her husband.

An inquest at Portsmouth heard that Mrs Brown's condition had worsened as she started to suffer from a condition called nystagmus, which meant that she had involuntary eye movements which stopped her carrying out activities such as drawing, reading or even watching television.

She also suffered from persistent nausea and anxiety.

The hearing was told that the 71-year-old, from Liss had made several attempts to commit suicide in the last three years but had been unsuccessful.

Detective Sergeant Glyn White, of Hampshire Constabulary, said that on one occasion Mr Brown had sat with his wife for 40 minutes after a suicide attempt before calling for an ambulance.

The couple then began discussing committing suicide together because Mr Brown did not want to go to prison for aiding a suicide.

Mr White said the couple visited known suicide spots but had decided not to because of the potential impact on other people.

Then on November 8 last year, the couple took a cocktail of drugs and attempted to gas themselves.

They left signs on the door of their home warning of fumes and not to enter the property until the emergency services had arrived and also wrote suicide letters and left a message on the work answerphone of their daughter-in-law, Mr White said.

When the emergency services were called, Mr Brown was found in a dazed condition and his wife had died in the bath where she had lay with a duvet covering her.

Dr Basil Purdue, a Home Office pathologist, said that a post mortem examination showed that she died of carbon monoxide poisoning.

Mr White said that Mr Brown, who had suffered several injuries during the attempt, was arrested and interviewed but later released without charge.

He said: ''This does appear to be a genuine suicide pact with both parties being willing participants.

''The whole family are now relieved that Helen's suffering is ended and Kenneth is freed from the burden of his wife's suffering.''

Dr Tracey Eddy, consultant psychiatrist, said that Mrs Brown endured an ''awful'' existence as she battled a very severe depressive illness worsened by the constant nausea and the eye condition.

Speaking of Mr Brown, she said: ''I believe he cared for Helen immensely and his whole day rotated around her needs.''

She said that they had investigated whether a neurological condition underlay Mrs Brown's illness but no answer was found.

Mr Brown sobbed as he told the inquest that his wife had a ''one-in-a-million'' condition and added: ''It's been difficult to bear.''

Recording a narrative verdict that Mrs Brown died as a willing participant in a suicide pact, Portsmouth coroner David Horsley said: ''It is almost unimaginable to think what life must have been life for Helen and all her family to go through this.

''She was an intelligent lady and she could see what was happening to her and I can quite understand why she might not want to her life to go on, it's an indescribable situation.

''I can only say how deeply sorry I am.''