A deadly assassin has got into Canterbury Cathedral to loot and pillage.

But there's no cause for alarm, because it's a fictional creation in the latest instalment of one of the world's most popular computer action games.

The iconic building features in Assassin’s Creed Valhalla, which was released last week and stormed to the top of the best-seller charts.

It is set in the 9th century when, in reality, it was one of the darkest period's in the Cathedral's history when a Viking army really did lay siege to the city until its defences were overwhelmed and the cathedral burned down.

Archbishop Alphege was captured by the Vikings and beaten to death with ox bones when he refused to be ransomed.

In the new game, created by Ubisoft, gamers play legendary Viking raider Eivor who leads raids against Saxon fortresses throughout England.

Among other locations, the adventure takes players into Canterbury where Eivor scales the old Saxon cathedral walls to gain access and loot the building.

Back then, it was a far less grand building than today's magnificent structure.

Cathedral bosses say they were not consulted about the site being included in the new game and only discovered by chance.

Spokesman Nathan Crouch said: "We were surprised to Canterbury Cathedral as one of the playable locations in the latest video game in the Assassin's Creed series.

"Two missions in the game – A Bloody Welcome and Search for Fulke – take place within Canterbury itself, requiring players to ride cross-country, infiltrate the city and then gain entry to the Anglo-Saxon Cathedral.

"While the real Canterbury Cathedral was not involved at all in the game’s development and was unaware that a fictional reconstruction of the Anglo-Saxon cathedral would appear, the cathedral and Vikings do share a fascinating, and often violent, real history."

Aelfheah (or Alphege) was the Archbishop of Canterbury when a large Viking army besieged Canterbury in September 1011.

After two weeks, according to the Anglo-Saxon Chronicle, they were treacherously let into the city. Many residents were killed, the city was ransacked, the cathedral was set ablaze, and Archbishop Alphege was taken hostage and held for ransom.

The ransom took time to raise but was eventually handed over. However, the Vikings returned to their ships at Greenwich with the Archbishop and demanded an additional ransom to release him.

Alphege ordered that the ransom not be paid, and, on April 19, 1012 during a feast, his captors got drunk and pelted him with ox bones, until one of the Vikings killed him with an axe blow to the head.

His body was taken to London and buried in the then St Paul’s Cathedral, and Alphege was later made a saint.

In 1023, King Canute, a Christian descendent of the Vikings, had St Alphege’s bones moved to Canterbury Cathedral, where they were interred on the north side of the High Altar, near to St Dunstan.

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