Only a particular species of creep could persuade me to write to the son of a friend and ask him to describe the death agonies of his beloved father. I typed that he must say “I would rather not talk about it” if he wished, then sent an email to Alexander Meleagrou-Hitchens.

I sat back, feeling dirty and not expecting a reply. I would not have troubled Alexander had not journalists at the nominally serious Times and BBC promoted the claim of a strange, spiteful book that Christopher Hitchens was “teetering on the edge of belief” as he lay dying from cancer of the oesophagus.

The Faith of Christopher Hitchens: The Restless Soul of the World’s Most Notorious Atheist is the work of a true fanatic, who has never learned when to seize a golden opportunity to hold his tongue. Recounting a memorial for Hitchens in New York, for instance, Larry Alex Taunton has to say how much he hates the event and the mourners. “The funeral, like the man himself, was largely a celebration of misanthropy, vanity and excess of every kind,” he intones.

Taunton says that Hitchens was his “friend”, but he marks his true friends and allies against a godly checklist and finds them wanting. The defender of the Christian faith spies Lawrence Krauss and cannot restrain himself from calling him “the smarmy little physicist Lawrence Krauss” (the professor is not only a renowned theoretical physicist but has also made the scientific case against the existence of a god or gods, ergo Taunton must jeer). Stephen Fry is not just an actor and writer but a “homosexual activist”. And Salman Rushdie becomes “the serial blasphemer Salman Rushdie”.

That last jibe gives you Taunton’s measure. Somewhat notoriously, Rushdie and his translators were targeted by the Ayatollah Khomeini for satirising the founding myths of Islam. In a choice between the atheist Rushdie and clerical murderers, Taunton, the Christian, instinctively decides to excuse the taboos of a deadly strain of Islam. Better to have a murderous faith, it appears, than no faith at all.

The true fanatic, in religion as in politics, judges the world by one standard. Taunton dismisses Hitchens’s prodigious learning as shallow because it did not lead him to the gospel. In a section that is tasteless even by his low standards, he ridicules Christopher’s father, Eric, as a weak man, because his failure to discipline his children “contributed to his son’s unbelief”. The book concludes by building to an anticlimax.

Like the cleverest spin doctors, Taunton gets the Times and others to suggest that the man he debated and travelled with experienced a deathbed conversion without quite saying that he did. Christopher stared “into the depths of eternity”, allegedly. He teetered on the edge of faith but did not, even in Taunton’s account, fall for it. The naive reader is left suspecting that, if only he had lived longer, Hitchens would have turned into a holy roller.

Good taste never worried Hitchens. When anyone accused him of speaking ill of the dead, however, he would smile sweetly and say that he had said just the same when they were alive. As I finished the work of Christopher’s “friend”, I reflected that pious grave robbers never follow his example and go public while their targets are alive, for they do not want to hear them deliver a public rebuttal.

I put the book aside last week. There seemed no need to write about Taunton, as Matthew d’Ancona and Padraig Reidy had already taken him to pieces with admirable vigour. But then Alexander Hitchens wrote back about that “bloody book”.

On the deathbed conversion – I spent my father’s final weeks and days at his bedside and watched him draw his final breath and die, and can assure you that there was no hint of any sort of conversion (as I’m sure you have already guessed). In fact, we barely spoke about religion at all except for joint expressions of frustration at the god botherers who made the rounds in the ICU and other units where dying people could be preyed upon by vulturous Christians.

I want to print what he said because lies on the web can last for ever and need to be countered. Indeed, they have always needed to be countered. In the 19th century, American believers claimed Tom Paine had died “howling and terrified”, recanting his assaults on organised religion and the reliability of the Bible.

After the New York Observer repeated the canard one too many times, the atheist Robert Ingersoll made a large bet that it could not justify the claim. He forced the editor to run a retraction headed “Thomas Paine died a blaspheming Infidel” when he won. Charles Darwin’s daughter, Henrietta Litchfield, had to go to similar trouble to stop the lie that her father on his deathbed had regretted his theory of evolution gaining credence.

One of the charges against Christopher Hitchens that has stuck is that he was a member a new breed of “militant” atheists that besmirched the genteel world of modern western culture. Hardly anyone who threw around the term worried about the moral equivalence they were drawing between men and women, who used only the power of language, and a wave of genuinely militant religion that crushed lives, sexually enslaved women and made medieval prejudices modern. Nor did they reflect that “faith-based” political action, from the Rushdie affair via 9/11 to Islamic State, placed a moral duty on atheists to adopt a more robust mode of argument.

I am delighted to say that Taunton’s sole achievement is to show us that, in death, Hitchens provided a further reason for militant rejection of religion: its creepiness.

It is only natural for a religious movement to rejoice at the conversion of an avowed enemy. If the critic is of sound mind and body, I would not object. Deathbed confessions are another matter, even if they are true. It is seedy in the extreme to seek recantations from people whose minds are failing and whose bodies are twisted with pain. The deathbed is the last place we will see. It ought to be the last place vultures fly to demand that we give a sober account of our beliefs.

Doubtless the willingness of believers to go further and invent conversions where none existed satisfies their infantile need for fairytale endings. But when they recite falsehoods over the corpses of Paine, Darwin and now Hitchens they move from the extremely seedy to the outright creepy: from vultures to vampires.