Nigeria's ruling party presidential contender Umaru Musa Yar'Adua says if elected in April he will continue the anti-graft policies of his predecessor.
"I will continue with this effort vigorously until every Nigerian, anywhere in the world, can proudly raise his head up," he told the BBC.
It was the first major interview the reclusive Katsina governor has given since his surprise December selection.
He looks to be favourite, as an opposition deal is close to collapsing.
It is now unclear whether they will be able to field a single candidate against Mr Yar'Adua.
President Olusegun Obasanjo steps down in April after eight years in power.
The polls should become the first transfer of power in Africa's most populous country from one elected leader to another since independence in 1960.
Mr Yar'Adua told the BBC's Hausa service that he would prosecute anyone who was corrupt, no matter how highly placed they were - stressing that this was vital to his country's standing in the world.
''If I become the president of this country, I am going to be fair and just.
"What the law says must be followed to the letter, irrespective of whether it is my son, my father or my brother. Who ever is found guilty will be prosecuted.''
He added that people now had confidence in Nigeria.
"We are tackling some of our problems, we are tackling corruption.
"You know that now Nigeria is in fact being de-listed from the list of the most corrupt countries in the world."
The Muslim governor has a reputation as having run one of the country's most honest state administrations.
Mr Yar'Adua also said that Africa would remain the cornerstone of Nigeria's foreign policy - and expressed his hope for improved bilateral relations with the rest of the continent.
Correspondents say the selection of Mr Yar'Adua by the People's Democratic Party (PDP) came as a surprise to most Nigerians.
His rise to power is thought to have come almost exclusively from the support he received from President Obasanjo.
But he said he was the PDP's consensus candidate.
"After due consultation my colleagues most graciously placed confidence in me - not because I'm better than anyone else - but that is what the consensus produced," he told the BBC's Focus on Africa programme.
"At the end of the day, as I've always said, it is God who chooses and that is what God has chosen."
He added that the choice of Jonathan Goodluck - the governor of Bayelsa State, in the troubled oil-rich Niger Delta - as his running mate was an attempt to give all parts of Nigeria "a sense of belonging".