Nigeria's richest man Aliko Dangote takes on the 'oil mafia'

Having built a $20bn oil refinery, Aliko Dangote is now at the heart of a row in the murky industry.

Nigeria's richest man Aliko Dangote takes on the 'oil mafia'

Having built a $20bn oil refinery, Aliko Dangote is now at the heart of a row in the murky industry.