More than 17,000 people have been killed and over a million others displaced as a result of the six-year insurgency by Islamist Boko Haram in parts of Nigeria’s North and neighbouring countries.

The figures were contained in an introduction to a video by BBC entitled ‘Inside Boko Haram’s stronghold’.

The video, uploaded yesterday on bbc.co.uk, features a report by BBC Hausa’s Jimeh Saleh, who “was granted exclusive access to Boko Haram’s stronghold in the Sambisa forest in north-eastern Nigeria.”

It said that Saleh travelled with the Nigerian Army “to see how far the region had come since Nigeria’s President Muhammadu Buhari vowed to crush the group by the end of 2015 when he was elected in May.”

Buhari and his information minister Lai Mohammed had last week claimed that Boko Haram had become largely defeated, only for the group to respond with a wave of attacks that claimed about a hundred lives over the weekend in Borno and Adamawa states.

•Photo shows Boko Haram insurgents.