"The Becket factor is surely integrity - the integrity of any man or woman who, seeing a duty, is prepared to face criticism, ridicule, and even death to see it done." (page 166)

Unlike other Becket fiction, this one is set in the twentieth century, and Becket, or rather his possible remains, is only a minor point, one mystery among several.  For some reason libraries seem to have deaccessioned this book, although they've kept the two sequels, Dark Provenance and Midnight Come.  The only explanation I can think of is that The Becket Factor is too dated, since it very obviously takes place during the Cold War.

Richard Harrison, retired from intelligence and now head of Canterbury's Diocesan Dilapidations Board, returns from a break to find that one of the cathedral canons has died.  He also glimpses a stranger in the cathedral during evensong, and not the usual tourist kind of stranger.  Back from church, he finds his former colleague, Brigadier Greville, waiting at his house.  Greville is in Canterbury to prepare for security for the next archbishop's enthronement, since the current archbishop has announced his intention to retire.  He (Greville) wants to know about Cratchley, the dead canon, and casts suspicion on the naturalness of his death.  Harrison sees a picture of Maurice Campion, Bishop of Derby, in the newspaper and recognizes the stranger from evensong.

Harrison meets with the archdeacon, Crocker.  Archdeacons, fictional ones anyway, are rarely very likable, and Crocker is no exception.  It doesn't help that his sister is dying of cancer.  Crocker is very high church and very conservative with regard to administration of the diocese.  He rejects Harrison's money-saving proposals if they would mean closing down old churches.  Tradition is important to him.

Repairs to the cathedral crypt floor have been ongoing, and, as always seems to happen, the project is behind schedule.  Then the workmen discover a coffin under the floor, with what appears to be a crozier etched on it.  Everyone immediately thinks that this could be where Becket's body was hidden from Henry VIII's men.  The dean of the cathedral worries that if it is Becket's bones in the coffin, the discovery will cause a schism in the Church of England, Catholic against Protestant.

Campion is on the news, criticizing the government's defense policies, especially nuclear weapons.  His uncompromising ethical stance makes him unpopular in certain circles, but he's a strong contender for the Primacy.  Many people, including the late Cratchley, think/thought he'll be the next archbishop.  Speaking of Cratchley, it appears that he was murdered.  According to Greville, traces of a fast-acting toxin used by the Eastern bloc were found at the autopsy.  Greville enlists Harrison to find out what the Becket factor is and why Cratchley was involved.  Harrison reluctantly agrees because he still feels guilt over setting up a Greek Orthodox priest to be killed when he worked with Greville in Cyprus.

Harrison starts investigating the Harvey-Watson papers.  Harvey-Watson was bishop of Manchester in the fifties, and Cratchley had been working on a biography of him.  Harrison discovers that Campion had been a disciple of Harvey-Watson, and an especially beloved disciple at that.  Was Harvey-Watson a Marxist?  There are suggestions in his papers that his sympathies lay that way, and he traveled incognito to Russia, accompanied by Campion, to meet with certain people.  Things aren't looking good.  "Cratchley murdered by a lethal injection when he's in the middle of writing a biography of a Marxist bishop - all this at the very time when the man's protégé is emerging as front runner for the Primacy!" (p 82).  Campion appears to be a Marxist, and Harrison thinks he knows what the Becket factor is.  Just as Becket, backed by Rome, had opposed Henry, so Campion, backed by Moscow, could oppose the current government.  Greville sees it as a plot to destroy democracy by constant criticism from a puppet archbishop.

Archaeologists from the British Museum arrive and raise the coffin, but the opening is delayed until after the holidays (it's almost Christmas).  Graffiti is discovered in the Lady Chapel, not long after someone had scrawled "Idolaters" on the vestry wall.

At the memorial service for Becket, held every year, Crocker makes everything as Catholic as possible and incites the congregation's great displeasure with these "Popish practices."  His sister takes a turn for the worse, and he asks to have the coffin opened earlier than planned, hoping perhaps that St. Thomas will intervene on his sister's behalf.  When the coffin is opened it proves to contain only animal bones, possibly a decoy to deceive Henry VIII's commissioners.  It's surprising that anyone would mistake a pig skull for human, but one of the archaeologists says, "We all tend to see what we expect."  Harrison realizes that he's been seeing the whole Harvey-Watson/Campion issue with the expectation of a communist connection.  Greville was using him for his own ends, to prevent a bishop he perceived as troublesome from becoming Primate of England.  The Russian connection does exist, but the people Harvey-Watson et al. had journeyed to meet turn out to have been oppressed Russian priests, nothing more.  The whole problem was baseless, a creation of Greville's paranoia.  Cratchley wasn't even murdered; he died of a heart attack.

Campion is chosen as the new archbishop.  He plans to dedicate his primacy to Becket's memory, and at the enthronement service he'll pray at the martyrdom pavings along with the dean and archdeacon.  More graffiti is discovered in Cratchley's old house: "For these are the days of vengeance."  On the day of the enthronement Harrison suddenly comes to the frightening conclusion that it's Crocker who's responsible for the graffiti.  Unhinged by his sister's death, opposed to Campion's politics, who knows what he might do.  Harrison rushes over to the cathedral, but he's wrong.  It's not Crocker who's the threat, but Canon Rope, a minor character, a friend of Cratchley's, who'd been slowly going crazy (he was always strange, so it wasn't easy to tell).  Rope tries to stab Campion, but Crocker throws himself in front of the knife.  He's killed, but he hadn't wanted to outlive his sister anyway.  And so everything turns out mostly all right.

The city pathologist, legally required to be present at the opening of the coffin, is the one who identifies the bones: a pig skull, ox tibia, horse fibula, some sheep and deer bones.  I'm surprised that he's so conversant in zooarchaeological matters, although, for all I know, he often has to distinguish animal from human remains.  Still, he seems awfully sure of himself that it's sheep and not goat, when the two are practically indistinguishable.  All right, I know I'm being pedantic, but this is touching on my own vocation here.

I could be offended by the archaeologists' "girl assistant," but I'd rather be amused.  I just hope no one thinks of me that way.

Addendum: When Harrison and his wife are watching the beginning of the enthronement on TV, they see the Queen and Prince Philip arrive, and the Prince and Princess of Wales (I told you the book's out of date).  However, I've recently learned that since 1848 no monarch has attended an enthronement.  It's the archbishop's big day, and they don't want to take attention away from him.