Atiku Abubakar, 76, is running on behalf of the main opposition People’s Democratic Party (PDP). He has run for the presidency five times before – all of which he has lost. Most of his career has been in the corridors of power, having worked as a top civil servant, vice-president under Olusegun Obasanjo and a prominent businessman. Just like Mr Tinubu, he has been accused of corruption and cronyism, which he denies.