Instead, in a tragic twist, the 80-year-old found herself charged with murdering Dennis, 81, after she survived the overdose both had taken at their Cannock bungalow early last year.
It was not the ending that either had envisaged when the hard-working and houseproud couple were well enough to tend to their much admired garden or take a spin in the car. However, as ill health set in, it was one they prepared for.
They were expecting to be found the following day by son Kevin who called every Tuesday to take his mother shopping, and who had been told many times of their intention to end their lives together.
Throughout the two-week trial at Stafford Crown Court the jury repeatedly heard evidence of the couple’s absolute resolve to carry out their plan.
Six months to live
The subject of suicide had first been raised by Dennis three years earlier within hours of him receiving a terminal bowel cancer diagnosis at Wolverhampton’s New Cross Hospital.
He was given six months to live but told his son on the journey home that he did not want to go through the same pain suffered by his best friend, also diagnosed with terminal bowel cancer.
The retired miner refused treatment for his condition, accepting only pain relief, and began researching assisted suicide through the Dignitas organisation in Switzerland.
Kevin Eccleston told the jury it became such an obsession with his father that he took away his laptop.
It did not take Mavis Eccleston long to come to the decision that she would die with her husband.
The mother-of-three had previously undergone a failed triple heart bypass operation and suffered from angina attacks.
The additional physical and emotional effort of caring for her chronically-sick husband was taking its toll on her.
There had also been allegations of harassment from neighbours in Raven Close, Huntington.
After that, talk of suicide dominated the conversation during visits by family members.
The couple had asked Kevin to “finish them off” with a pillow over their faces if he found them still alive after a suicide attempt.
'We're going together'
He told the jury: “They’d both had enough. Dad was in severe pain. My mom loved my dad so much, she wanted to die with him.
"Dad was the same – he’d say ‘we’re going together’. Every day I saw him, literally 20 or 30 times a day, he would go on about it. It just became a topic.”
Joy Munn said it had been “heartbreaking” to see how her mother, once so “energetic and full of life”, had deteriorated. She had offered to look after her so she wouldn’t be alone if Dennis went through with his threat.
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“She held my hands and said ‘Joy, I love you with all my heart but I love your dad more and that’s where I want to be’, and I knew then that’s what she wanted,” Mrs Munn told the court.
The final straw came in the early hours of February 19 last year after Dennis had fallen in the night.
Mavis, on her hands and knees, had managed to get him into his recliner armchair.
As she did so she noticed a growth on his groin, something he had kept from her, and realised the extent of his pain, she told police.
This was the moment that she agreed to his pleas to help him “go now” by preparing an overdose of his medication.
In her grief and confusion, Mavis gave different versions of what happened next.
Asked by nurses at Stafford Hospital, where the couple were taken, whether Dennis knew she had given him a potentially lethal dose, she replied that he hadn’t, prompting staff to contact police.
But to detectives she denied making that admission, saying that Dennis “knew full well” what he was taking. In the witness box she said he took an active part, removing the tablets from their packs while she ground them into a powder, leading her to tease him that he had “the easy job”.
Before taking her own overdose, she made sure that Dennis was settled and safe, kissing him on the head and pulling a cover over him before wishing him “goodnight, darling”, the jury heard.
She then finished a 14-page suicide note explaining their intention and lay on the sofa.
The chance arrival of an unsuspecting Aimee Smith later that morning upset the plan but saved her grandmother’s life.
After the verdicts Joy Munn, Dennis and Mavis's daughter, read a statement on behalf of the family calling for a change in the law.
"Our dad would have been devastated at the thought of his beloved wife waiting to find out if, at the age of 80, she would face a life sentence in prison simply for respecting his wishes, the 54-year-old said.
"He would have been heartbroken if he had known his wife and family would have had to endure 18 months of extreme anxiety and distress.
"We believe there must be a change in the law so that dying people are not forced to suffer, to make plans in secret or ask loved ones to risk prosecution by helping them, and so that no other family has to experience the pain our family has had to endure. "
The Crown Prosecution Service said it was in the “public interest” to prosecute Mrs Eccleston.
A spokesman for the CPS said the decision to prosecute the 80-year-old was only taken after “detailed and careful examination” of all the evidence available.
“These events were clearly very distressing for everyone concerned and I would express my gratitude to the family of Mr and Mrs Eccleston for the dignity and understanding they have demonstrated throughout this difficult process," the spokesman said.
“It is not the role of CPS to determine guilt or innocence. The CPS is responsible for deciding which cases should proceed applying the Code for Crown Prosecutors.
“The decision to prosecute in this case was taken only after detailed and careful examination of all of the available evidence, including statements from family members and expert witnesses.
“Following this review we concluded that there was sufficient evidence to provide a realistic prospect of conviction for the offences of murder and manslaughter and it was in the public interest to prosecute.
“We respect the verdicts reached today by the jury.”
Detective Inspector Cheryl Hannan, of Staffordshire Police’s Major Investigations Department, added: “This has clearly been a distressing case for the family.
“We have carried out a professional investigation in accordance with the law, mindful of the tragic circumstances, and a file was submitted to the CPS.”