The Norwegians raided during the winter between 840 and 841, rather than the usual summer, having waited on an island off Ireland.

So far this year they have raided more than 50 vessels, stealing cargos and hijacking ships, from private yachts to oil tankers, and extorting some 100 million a year in ransom.

In the extract, Linton says she had come to Africa with hopes of helping some of the world's poorest people, but describes being forced to later flee for cover deep in the Zambian bush under the dense jungle canopy when armed rebels from neighboring Democratic Republic of Congo raided the village where she lived.