He said his first letter was published 60 years ago and asked that this, his last letter, would also be published.
He then outlined the couple's reasons for ending their lives: "We have each reached the point where all the finest available treatment and TLC can no longer attain the desired and acceptable level to support an enjoyable and worthwhile life.
"To force the issue beyond this point would mean for us a living death; we have therefore chosen to peacefully end our lives."
Below a typed part of the letter Mr Milner had made some handwritten notes, which read: "Arranging this so that it does not fail has been very difficult and traumatic for us. This need not and should not be the case.
"I have made many visits to friends and relatives in care homes. They cannot wash, dress, feed or toilet themselves. They cannot get out of the chair or walk. This can go on for a long time - years.
"Long before we reach this stage of degeneration the quality of life for us would be unacceptable, cruel and inhumane."
Mr and Mrs Milner's daughter Chrissy said her parents had been in good health but did not want to get to a stage where they would be too ill to care for themselves. She said they felt they had to pre-empt any possible serious deterioration in their health.
Chrissy and Nigel support their parents' decision to take their own lives
"I think they made this decision because they'd had a very positive life. They'd enjoyed life," she said.
"They'd always said they wanted a positive death, they wanted a good death."
She said she and her brother Nigel knew they had formed a suicide pact but did not know when they planned to kill themselves.
She said they had told her: "We won't be here for Christmas."
Chrissy said: "My brother and I fully endorse what has happened.
"If they were here now we would give them our full support because it was an idea, a concept, that was very close and dear to them."
Mr and Mrs Milner's statement, sent with the letter to the BBC and headlined "a personal critical self assessment", appeared to be signed by both of them.
Assisted suicide laws
Anyone helping someone kill themselves in England or Wales could face 14 years in prison
In Scotland and other European contries the law is less clear, some have more liberal laws
In Switzerland, organisations like Dignitas help people end their life
To date, more than 100 UK citizens have travelled to Dignitas to end their life.
It read: "We have been fortunate to have lived through and enjoyed 80 plus years of a happy, loving and exciting life.
"It would be impossible to thank all the people and organisations which every day, without fail, have contributed to our lifespan.
"There's just one outstanding [group] which we think everyone would go along with, the medical profession and the NHS in which they serve. They have usefully extended our lives by at least 25-30 years.
"We leave this life with just one serious and disappointing criticism of our society.
"Today we have been denied what we believe to be our basic human right - to terminate our own lives, in our own home, at our own choosing, with our loved ones around us, without anyone having to face any legal possibilities or harassment."
'Action through fear'
Sarah Wootton, chief executive of Dignity in Dying, said: "We are saddened by the news of Dennis and Flora Milner's deaths.
"Their case highlights some people's deep concerns about suffering unnecessarily at the end of life, and the lack of a safeguarded choice which can prompt people to take drastic action through fear."
A Thames Valley Police spokesman said: "We were called to an address in Enborne Road at 9am on the 1 November. There were two unexplained deaths, they are not thought to be suspicious."
An initial post-mortem examination has been carried out but further toxicology tests were needed to confirm how they died, he said.
A spokesperson for the West Berkshire Coroner said the couple's family had been told.
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