Boko Haram is singling out geography teachers in its campaign of terror against Western education in Nigeria, it has been revealed.

Teachers of the subject have emerged as an unlikely top target for the group because their lessons contradict its bizarre worldview on how the Earth was created.

Boko Haram believes that the Earth is flat rather than spherical, and that rainfall is caused not by evaporation, but by God’s divine will.

As such, geography teachers are ranked alongside Nigerian security chiefs and senior politicians as prime candidates for assassination.

The threats to geographers are outlined in an extensive new report by Human Rights Watch, which lays bare the devastating impact wreaked by Boko Haram on Nigeria's school system.

It says that a total of 600 school staff have been murdered by Boko Haram since 2009, and that 19,000 have quit their jobs due to threats and attacks.

“Boko Haram insurgents have shown particular distaste for certain subjects like geography."

The report is timed to coincide with this Thursday's two year anniversary of Boko Haram's kidnapping of more than 200 schoolgirls from the town of Chibok in Borno state in north-east Nigeria. They remain as hostages to this day.