The more Dexter spoke yesterday, the more it became clear that the detective's state of health - physical, mental and spiritual - mirrors that of his creator.
The novelist called a press conference to confirm that Morse, as long rumoured, does indeed expire in the latest and last novel which is in the shops today. He dies of complications from diabetes, exacerbated by too much alcohol.
Dexter has diabetes and said yesterday: "I was up all night eating cereal and sugar. I have a lot of trouble with my diabetes, which is not helped by my one vice. I drink far too much alcohol."
Both novelist and detective are aficionados of philosophy, literature, music and The Archers. Morse is turning 70, Dexter is turning 69. Rarely has a novelist had so blatant an alter ego.
In such circumstances, sending your hero to his grave is a bold move. But, in chapter 74 of The Remorseful Day, Morse falls into a diabetic coma at home. However, he regains consciousness and is able to dial 999.
He contemplates death while being ferried to hospital in the ambulance and wakes to find his long-suffering colleague Lewis by his bed. In the next chapter his condition is "critical but stable" and, shortly after a glass of whisky, he tells the nurse "thank Lewis for me". But the nurse does not hear him properly.
Art mirrors life. At yesterday's press conference in London, Lewis was yet again not there to hear what was being said. Morse's television persona, John Thaw, was at the novelist's side. But Lewis, or rather the actor Kevin Whately, was absent. He is undergoing a trauma that even the king of detective thriller writers cannot solve - contractual difficulties with ITV, which could even keep him out of the final Morse television film, when the new novel is filmed next year.
Dexter, though, was on form and needed little help in addressing his hero's demise. "I'm naturally saddened," he said, "to take leave of the melancholy, sensitive, vulnerable, independent, ungracious, mean-pocketed Morse. He has lived with me now for more than a quarter of a century.
"With the body count in books and on TV risen to almost 80, Oxford has become the murder capital of the UK, and the time has come to put an end to this."
Dexter added: "Various possibilities suggested themselves. Retirement perhaps; perhaps less probable, marriage; failure in a case; the sack; nervous breakdowns; death while performing CID duties, or death when he was not on duty.
"I decided myself that Morse must die."
Dexter said that Morse would be turning 70 next year and he suspected few people got better as they got older. Was he talking about Morse or was he talking about himself? Again the two appeared to merge.
"Certainly," he ruminated, "in the last few years I have found it increasingly difficult to pursue the lonely and demanding discipline of writing. It is time for me to finish, too."
John Thaw, who first played Morse in 1987, said he was saddened by the character's death. "It is a great pity that the old chap's got to go. I think we'll miss him in a lot of ways.
"But if Colin Dexter says Morse is dead, that is good enough for me. I would not make any more films about Morse after his death."
Morse fans will find in the last book that their hero appears reluctant to reopen an unsolved murder case, which may lead them to the conclusion he is implicated in the death in some way. Devotees have to wait until the last chapter to clear up the mystery and establish the truth.
As for Morse's death, it is an ill wind ... The British Diabetic Association last night used it for a new publicity campaign. "Had he pursued a healthier lifestyle," it said in a statement, "he could have continued to be the scourge of the criminal element for many years to come."
John Walsh, Review, page 4
DETECTIVE DEPARTURES: THOSE WHO WENT BEFORE
The deerstalker-wearing detective originally died in a cliff top fight with arch enemy Professor Moriarty. His creator, Sir Arthur Conan Doyle, finished off his hero because no one took his other fiction seriously. However, Holmes returned in The Adventure of the Empty House, explaining to Dr Watson that he had beaten Moriarty by wrestling him over the edge of the falls.
The Belgian detective created by Agatha Christie and famous for his "little grey cells". He dies after refusing to take his medicine, thereby concealing the identity of the murderer in his final mystery. Christie wrote the book, Curtain, during the Second World War because she was afraid that she might die, but her publishers persuaded her to place it in a bank vault.
Van der Valk
The Dutch detective who worked in Amsterdam was the basis for a 1970's television series and was killed off by author Nicolas Freeling, a cook married to a Dutch woman. The author angered many readers when his hero was shot dead less than half way through A Long Silence, the last of eleven books. In The Widow, the detective's wife, Arlette, became the hero.
Sir Frances Varney
Known as Varney the Vampire, he was an anti-hero and the first popular fictional character to be killed-off by a bored author, James Malcom Rymer. Mr Rymer wrote the serial, The Feast of Blood, which was over a million words long, between 1845 and 1847.
Varney ended his days by throwing himself into Mount Vesuvius, because like the author, he was bored.