Another damning report has exposed the depth of corruption in Nigeria, a country where the report said the leaders have been licensed to loot her treasuries.

The report by Channel 4 News, UK based news channel claimed that the breath-taking scale of official corruption is blighting the lives of more Nigerians than even the deadly insurgency.

It also quoted a former Nigerian government minister as saying that “Nigeria, is a country where you can disappear an elephant into the pocket of a shirt.”

The minister claimed that his civil servants offered him a 20 per cent slice off his department’s multi-billion dollar budget, assuring him they could bury their tracks.

Their expectation, he said, was that they too would be rewarded with a generous tranche of the loot.

The senior politician, who cannot be named for his own safety, alleged that he had been approached shortly after his appointment to cabinet, while staying in a hotel on a high-profile foreign trip.

He told Channel 4 News that he refused the offer, telling his civil servants that he wouldn’t be able to sleep at night.

“The scale of corruption by this country’s political elite is breaking people,” he said. “Some see it as the dispensing of patronage, so they can survive. But let’s say it straight. It is theft. Theft with a sense of entitlement.”

Jonathan Miller of Channel 4 News said that a couple of days later, “I was interviewing Nigeria’s flamboyant finance minister. Inevitably, before long, our conversation homed in on the C-word. “Your country has become a byword for corruption,” I said.

“I reject this completely!” Ngozi Okonjo-Iweala, shouted indignantly at me across the six-foot gap between our two armchairs in her ministerial office, strewn with photographs of herself with world leaders past and present.

“This country has a tendency for people to throw out wild numbers and because of the perception of corruption, people believe a lot of this. Nigeria is not a lawless country where you just lob accusations.”

Dr Ngozi, who earned her doctorate from MIT and who has spent years as a managing director of the World Bank, has a street named after her in Nigeria’s capital, Abuja. Half way along it, there’s a slum called Utako, whose residents live hand-to-mouth. Few have jobs; the rat-infested, malarial shanty lacks all basic services.

“The masses are suffering because of the greediness of our leaders,” said Stanley, a man in his late 20s, and one of the millions of Nigerians who do actually believe the “wild numbers” but are powerless in their poverty to hold their leaders to account.

“They are so corrupt don’t care about the masses,” he said. “All they care about is how to embezzle our money. If you look around this place, there is no sanitation, no water, no electricity. They don’t live in this environment.”

Nigeria now ranks as Africa’s largest economy, powered by vast oil reserves. Average incomes have doubled since 2010, yet a third of Nigeria’s people live on less than one pound a day.

For decades, it has been alleged that corrupt politicians were skimming huge sums off the national oil revenues – hundreds of billions of dollars according to the UN.

Most of Nigeria’s 500 languages don’t even have words for “million”, let alone “billion”, but people know the score. Power is perceived as the licence to loot.

Until last year, these “wild numbers” were indeed just “thrown around,” as the finance minister put it. Then, finally, a whistle-blower emerged who put some flesh on the bones.

The numbers were indeed wild. But he came with some pedigree. The Governor of the Central Bank of Nigeria was no ordinary whistle-blower.

Dr Lamido Sanusi, who had been awarded “Central Banker of the Year 2010″ by the Financial Times Banker magazine (an award which cited his “radical anti-corruption” campaign) discovered what he figured was a US$20-bn black hole in Nigeria’s national finances.

He wrote to President Goodluck Jonathan, detailing the mechanisms by which be believed an astronomical fraud had been committed.

 He calculated that over the course of a year and a half, a billion dollars a month had been siphoned off national oil revenues. These “leakages” were, Dr Sanusi told the president, “unsustainable”.

For his trouble, the president first suspended, then fired him, accusing his central bank governor of “financial recklessness”.

Last month, Dr Sanusi, a blue-blooded descendent of the Kano royal line, was reincarnated as the northern kingdom’s new emir.

He swapped his pin-striped suit for flowing robes and a turban. Sitting in his throne room the day after his coronation (pictured below), HRH Muhammad Sanusi II told Channel 4 News exactly how he believed the alleged fraud had been perpetrated. He sticks by all his allegations.

“At the heart of the problem, to my mind,” he said, “is that the entire political system is held hostage by a small group of vested interests.”

His was an almost identical assessment to that offered by Stanley in the slum on Dr Ngozi Okonjo-Iweala Street, where most people I spoke to knew all about the former central bank governor’s staggering allegations.

But Dr Ngozi herself dismisses his claim. “It just so happens that on this that he was not correct,” she said. Last year, she claimed more than US$10bn was “missing”.

The Nigerian government commissioned an independent “forensic audit” to determine the truth, but has chosen only to publish edited highlights of the final report – and many Nigerians still smell a rat.

Nigeria ranks 136th out of 175 countries surveyed for Transparency International’s Corruption Perceptions Index – which measures how corrupt a country’s public sector is perceived to be.

Obiageli Ezekwesili is Transparency’s co-founder. She too has served with the World Bank – as its vice-president for Africa – and as a Nigerian government minister.

“There is nothing cultural about corruption in African societies. What has happened is that the is an alienation of the systems and institutions of governance from the people,” she said.

“So when you see elite greed manifested in grand corruption, perpetrated over time, it is simply that nobody has made the link to the fact that government owes us something.”

Oby Ezekwesili remains optimistic about Nigeria, despite its politicians’ winner-takes-all approach. “Give this country about a decade and a half, it won’t be the same. You know, when citizens awaken to the power of the office of the citizen, no society remains the same.”