Problems pile up for Nigeria as sick President stays out of view

Nigeria has begun the new year in the grip of a constitutional crisis as the mystery over the health of its President, who is believed to be in hospital in Saudi Arabia, deepens. No one knows who is running Africa's most populous country, prompting warnings that a dangerous power vacuum is developing in a country with a long history of military coups.

President Umaru Yar'Adua has been out of the country for more than a month, but his medical condition remains unclear and there is no agreement on a succession. Vice-President Goodluck Jonathan, who has not had executive power signed over to him, has been reduced to giving vague reassurances such as "the ship of state continues to sail".

The 58-year-old president, known as "Baba Go-Slow" to many in Nigeria due to the sclerotic pace of reform, has a long-standing kidney complaint and was flown to a clinic in the Saudi city of Jeddah on 23 November with chest pains. He has since been diagnosed with acute pericarditis, an inflammation of the membrane around the heart that restricts its action. No further details have been revealed about his condition. Lawyers are pushing for an independent medical examination to establish his fitness to govern.

The election of Mr Yar'Adua, a Muslim and northerner, saw the first democratic transition of power since Nigeria's independence and was meant to signal a new era.

But election observers concluded that the poll was seriously flawed. Mr Yar'Adua – who was chosen by the ruling party and previous president, Olesegun Obasanjo – had to fight off nearly two years of legal challenges from those demanding a rerun. The uncertainty over his health has come as Nigeria faces a security crisis over the would-be Christmas Day bomber, Umar Farouk Abdulmutallab.

Meanwhile the fragile peace in the oil-rich Niger Delta is in danger of unravelling, and two of the country's largest oil partners, Chevron and Royal Dutch Shell, whose activities underpin the economy, are renegotiating terms. Addressing the nation on New Year's Day, the Vice-President said, "Although Mr President has been away from us for some time on account of a medical condition, he has maintained sustained interest and optimism ... We are hopeful Mr President would return to us before long."

This has done little to convince the opposition that Nigeria is not in a dangerous drift. "The vacuum in governance is doing untold damage," said opposition spokesman Lai Mohammed.