When Charles Soludo, Nigeria’s swashbuckling central bank governor, raised the minimum capital requirement for the country’s 90-odd banks, the north of the country was left with only one it could call its own.

Unity Bank was the outcome, according to a senior employee, of a mind-bogglingly complex merger between nine banks with majority northern interests. Even then, the largest single shareholder became the government of the southern oil-producing state of Rivers.