The British Museum’s latest exhibition will feature “rediscovered” wooden figures that appear to confirm ancient Peruvians were rowing prisoners of war to a tiny Pacific island for ritual sacrifice.

The carvings, depicting rope-bound captives, are shrouded in mystery.

Ceramic evidence found on the Peruvian mainland depicts a warrior from the Moche civilisation being taken on a reed boat to Macabi, a small rocky outcrop off the coast of northern Peru, but the island itself has never had proper archaeological work done on it.

The Moche culture existed in northern Peru from around 100AD to 800AD.

The carvings were discovered in caves on the uninhabited island in the 19th century by a British company mining for guano, the solidified excrement produced by seabird colonies, which is an exceptionally effective fertiliser.

Its chemical properties are believed to have helped preserve the figurines, which date to between around 400 and 800AD.

“The toxic environment stops oxygen from getting in”, explained Dr Jago Cooper, the head of the Americas at the British Museum.

The sculptures were then donated to the British Museum in 1871 and while curators knew of their existence, they had lain largely undisturbed and unstudied for 150 years until preparations began on the exhibition, entitled Peru: A Journey in Time.

As part of those preparations, five figures were selected to be displayed and had conservation work and basic analysis performed on them.

It is common for large museums, whose collections can total millions of items, to have many unstudied objects.