By Alex Last
BBC News, Nigeria
Governor Umaru Yar'Adua is the front-runner to be Nigeria's next president after elections in April.
Governor Yar'Adua said the "era of the ruling elite is over"
He is the candidate of the governing People's Democratic Party, the PDP.
He is backed by outgoing President Olusegun Obasanjo, and so has access to the money, power and political machinery needed to win a Nigerian election.
But he is not well-known outside his state of Katsina, in the Muslim north of the country.
So he is on the campaign trail across Nigeria to introduce himself.
Almost daily he is the focus of colourful, noisy political rallies at stadiums in front of thousands of bussed-in supporters.
In between he holds quieter meetings with powerful local party members - people who can really carry the vote.
Softly spoken, tall and thin, Mr Yar'Adua was once a chemistry teacher, who comes from a northern Nigerian political dynasty.
His late elder brother, was an army general, who served as deputy to Mr Obasanjo when he was Nigeria's military ruler during the 1970s.
In his youth Umaru Yar'Adua, was known for being left-wing , and even now - as member of the northern Nigerian Muslim aristocracy - he has distinct views on what is expected when he is in office.
"I will be a servant leader" he told the BBC on the campaign trail in south-eastern Nigeria.
"The era of the ruling elite is over," he said.
"The ruling elite in Nigeria, I am sorry to say, have the conception that those in the position of authority and leadership tend to be privileged, and sometimes even consider themselves above the law.
"I want a situation in Nigeria, that if I become president, everyone knows I am in the office as a worker, and doing a job. And that job does not make me any different from any other Nigerian."
The fact is that Governor Yar'Adua was little-known before he won the party's ticket with presidential backing in December.
Governor Yar'Adua's running mate is Goodluck Jonathan
Though his supporters say he is strong-minded, some have suggested that President Obasanjo - after leaving his office - will still try to exert control over his anointed successor.
"I will be as independent as the constitution of Nigeria allows," said Mr Yar'Adua.
"I am there to implement the manifesto of my party, the PDP, but the party will not come and say it will run the government. Because I will run the government as president of Nigeria, not as president of the PDP."
Mr Yar'Adua is seen as close to the small reformist camp inside the current government.
Under President Obasanjo, the government has introduced IMF-backed reforms which have brought some control to public spending, increased foreign reserves and won debt relief from rich creditor nations.
But few Nigerians say they have seen the benefit of the reforms, with the majority of the country's 140m population still living in poverty.
"It will take time. The positive impact of these changes will not manifest until some years after," Mr Yar'Adua said.
He said he would focus on a seven-point plan to deal with the country's most pressing problems.
He said he would declare a national emergency on power and energy to deal with the lack of electricity and reform land ownership in the country.
"You find millions of people in Nigeria who own farmland but cannot bring them as assets into the market and get credit to go into production and create wealth," Mr Yar'Adua said.
One of his main challengers for the presidency is a retired former military leader, Gen Muhammadu Buhari, who was famous for his war on corruption in the 1980s.
Gen Buhari is famous for his war on corruption when in power
Gen Buhari has a lot of popular support but many say he does not have the money or the political machinery to win.
The other main contender is Vice-President Atiku Abubakar, but his election chances are in doubt because of allegations of corruption which the government says will bar him from contesting.
Fighting corruption is a major issue in Nigeria - estimates say the country has lost almost $400bn (£204bn) to graft.
It became endemic under military rule, and is still pervasive despite the much-publicised anti-corruption effort.
But the government has been accused of using the anti-corruption campaign to target its political opponents, and disqualify them from running for office in the polls.
But Governor Yar'Adua defended the government's actions.
"Corruption is evil. It is a major disease like a cancer, which eats up a society gradually until it is stopped.
"I think the level and proportion that corruption has taken in Nigeria, to the extent that it was threatening to become a national culture, needs to be fought vigorously and on all fronts.
"As far as I am concerned, the anti-corruption war that is being fought today is correct," Mr Yar'Adua said.
In Nigerian politics, support for a candidate and a party at all levels is largely seen as an investment - often financial - which is expected to be returned with interest once in office.
Mr Abubakar has denied allegations of corruption levelled against him
So it is not clear just how Mr Yar'Adua will handle the powerful interests he will encounter if he gets power.
In any case, the pressure attached to leading a country like Nigeria, with its huge population, vast bureaucracy and powerful local state interests, is immense.
Given that Governor Yar'Adua has been receiving treatment for a kidney illness, some have questioned whether he is up to the task.
"I have the health of a normal 56-year-old," he said at the end of the interview.
"I was sick in 2000, when I had an illness and was treated, and I recovered. I am a normal person, I have been ill at various times of my life, and I am satisfied with my health.
"I am interested to know anyone who can guarantee his health or his life or his death," Mr Yar'Adua said.