Sunday, December 29: a murder is announced.

The victim: Thomas Becket.

First information report: The victim was targeted in cold blood by four assassins as eyewitnesses looked on.

But this is a case, not for Scotland Yard, but the British Museum which points out that the murder took place exactly 849 years ago on December 29, 1170, and the four knights who carried out the killing of the Archbishop of Canterbury inside his own cathedral claimed immunity of sorts because they felt they were acting on behalf of King Henry II.

Had not the four — Reginald FitzUrse, Hugh de Morville, William de Tracy and Richard le Breton — heard their monarch say: “Will no one rid me of this turbulent priest?”

Other historians (e.g. Simon Schama) claim the King didn’t exactly say that but the four knights, anxious to get into his good books, heard what they wanted to hear. Some will see parallels with the slaughter of the Saudi journalist, Jamal Khashoggi, and whether those who butchered him were acting on behalf of the kingdom’s crown prince, Mohammad bin Salman.

At any rate, a yearlong programme of events marking the 850th anniversary of “one of the most shocking crimes in European history”, has been unveiled by the British Museum.

The exhibition at the British Museum “will showcase an incredible array of over 100 objects associated with Becket, including manuscripts, jewellery, sculpture, stained glass and paintings, and will feature artefacts from the museum’s collection as well as important loans from the UK and around the world.

“It will present Becket’s tumultuous journey: from London-merchant’s son to Archbishop; and from a revered saint in death, to a ‘traitor’ in the eyes of Henry VIII, more than 350 years later.”

Naomi Speakman, co-curator of the British Museum exhibition, said: “The story of Thomas Becket’s life, death and legacy has all the hallmarks of a Game of Thrones plot. There’s drama, fame, royalty, power, envy, retribution, and ultimately a brutal murder that shocked Europe.

“These events had repercussions that have echoed out through time and we’re delighted to be telling this important story for the first time in a major exhibition.”

Becket was quickly canonised a saint by Pope Alexander III and his shrine at Canterbury became a major centre of European pilgrimage before being destroyed on the orders of Henry VIII in the early years of the English Reformation.

Becket2020 will see venues in London, Canterbury and beyond host a range of events across the year to commemorate his murder. The programme includes performances, pageants, talks, film screenings and religious services.

A major new production of T.S. Eliot’s Murder in the Cathedral will be performed for the first time in Canterbury Cathedral in October in a joint initiative with the local Marlowe Theatre.

The current Archbishop of Canterbury, Justin Welby — he had prostrated himself at the Jallianwala Bagh memorial in Amritsar in September — will preach at Southwark Cathedral in December 2020, in commemoration of Becket’s final sermon which took place at the same site shortly before his death.