Less than five years ago, on July 30, 2009, an eccentric Islamic cleric and cult leader in Nigeria's remote north-east was handcuffed and paraded before TV cameras, then put up against the wall of the main police station in Bauchi City and summarily executed, along with seven of his colleagues, by police marksmen.

Yusuf Mohammed's sect had been born in 2002, growing out of an ultraconservative Islamic movement of well-educated students. The group, initially purely religious, slowly grew overtly political. Its adopted name, Boko Haram, has many interpretations in the northern Nigeria Hausa language, but one of the most common goes: "Western education is deceptive and sinful and is forbidden." In Hausa, the name is apparently rich in ironic religious and social meaning.

The charismatic Mohammed, who drove a silver Mercedes-Benz, preached that the concept of a spherical Earth was contrary to Islamic teaching and should be rejected, along with Darwinian evolution.

Beyond that police station in July 2009, Nigerian soldiers and police units went on a rampage in Bauchi in which, according to diplomatic cables recently released via WikiLeaks, an estimated 700 to 1000 people, including civilian bystanders, were killed.

The followers of Boko Haram - which has garnered international attention after it kidnapped 276 girls from a school in the village of Chibok last month - recall the Bauchi Massacre as the decisive moment in their resort to intense and widespread violence that has spread havoc both within and beyond the northeast of Nigeria, a region which borders Cameroon, Chad and Niger.

True, Boko Haram had provoked the indiscriminate 2009 crackdown by the security forces by itself launching an attack beforehand with about 70 fighters, armed with guns and hand grenades, on a mosque and police post in Bauchi, a city about the size of Edinburgh. The diplomatic cables said that 55 people were killed in that attack.

This was one of the first known assaults by Boko Haram as it tapped in to growing anger among northern Nigerians about their poverty and humiliating and violent abuses by government security forces. Mass killings involving campaigns by different groups for the introduction of Islamic sharia law, clashes between Muslims and Christians and outrages by government police and soldiers had punctuated life throughout northern Nigeria since 1999 without making international news agendas or triggering attempts at wise solutions by the Nigerian government. Boko Haram's Bauchi attack, appalling though it indisputably was, was just part of a pattern of decade-long abuses throughout the north.

Critically, however, the uncontrolled retaliation by soldiers and policemen in Bauchi led irrevocably to Boko Haram's latest atrocities which finally moved it to the top of the world news agenda - probably to the great satisfaction of Mohammed's successor, Abubakar Shekau, who has said he wants to bring down all of Nigeria, with its 175 million people, delusional though that might be.

Just three weeks after the Bauchi Massacre, al-Qaeda in the Islamic Maghreb (AQIM) - originally an Algerian Islamist insurgency linked to the global al-Qaeda network - issued a statement expressing "brotherly sympathy" with Boko Haram.

The core of the insurgency's activists scattered to other African countries where they received welcomes from al-Qaeda affiliates. The Algerian government said some Boko Haram fugitives received religious and military training in Algeria from AQIM fighters. Others trained in Somalia with the al-Qaeda affiliate there, al-Shabaab; some went to Yemen.

By late 2010, the Boko Haram men were returning to northern Nigeria, militarily more sophisticated and better equipped under a new leader, Shekau, formerly the group's second in command.

It was Shekau who, in a video released last week by the insurgents, described the kidnapped Chibuku schoolgirls as "slaves" and went on: "By Allah, I will sell them in the marketplace … God instructed me to sell them, they are his properties and I will carry out his instructions. I will marry off girls at the age of nine and 12."

The renewed Boko Haram began a campaign of assassinations from motorbikes against Nigerian government officials, police officers, journalists, villagers, students and churchgoers. Soon its fighters were also equipped with pick-up trucks mounted with artillery: the vehicles and weapons, Nigerian officials have said, were traded out of Libya after the overthrow of Muammar al-Gaddafi. Today, Boko Haram even has tanks and armoured cars, though it is unclear, as yet, how the group acquired them.

The attacks under Shekau have become more indiscriminate. The leader claims to be in direct communication with God, and he has said the main purpose of the violence is to demonstrate the impotence of the Nigerian state, which he has effectively achieved.

And although Boko Haram's brutality is appalling beyond description, the organisation does have popular support. The northeast is economically depressed and among the least educated regions in Nigeria. Shekau has done a good job of convincing residents that the rulers in Abuja, the national capital in central Nigeria, are corrupt and that a better system of government would involve strict enforcement of sharia law across Nigeria, plus the denial of education to women. And his promises, coupled with weapons and a licence to plunder, have been enticing to hundreds of unemployed young men.

The central government's heavy-handed and ill-disciplined anti-terrorism campaign has just helped create more members to sustain Boko Haram. Nigeria's Human Rights Commission last year accused the military of arbitrary killings, torture and rape in its campaign against the group. This makes for fertile territory for Boko Haram.

The Nigerian military has touted Shekau's death several times, only to retract its claim after he appeared alive in propaganda videos.

President Goodluck Jonathan last week assured Nigerians that the national government was doing "everything possible" to return the kidnapped Chibok schoolgirls to their families. But a Chibok elder, Pogu Bitros, dismissed this as "mere talk", and said the community had no confidence that the government and its security arms would do now what they have failed to do for several years - achieve security for ordinary people in the northeast and beyond. Bitros's sentiment is shared by many Nigerians.

Jonathan finally swallowed his pride last week and for the first time embraced international help in an attempt to counter Boko Haram and to try to free the Chibok girls. This weekend, speaking instead of her husband in the weekly US presidential address, First Lady Michelle Obama said she and her husband were "outraged and heartbroken" over the abduction of the schoolgirls.

As the United States set up a dedicated "co-ordination cell", staffed with intelligence, military and law-enforcement specialists in its Abuja embassy to advise and help the Nigerians, a team of British "experts", including defence and intelligence officials, diplomats and aid workers, also arrived in the Nigerian capital. According to a Foreign Office statement, they "will be working closely with US counterparts and others to co-ordinate efforts, as well as looking at longer term solutions to the crisis."

The "others" include personnel from France, which has been waging military campaigns against Islamic fundamentalists in Mali and Niger, and from China, which has huge economic interests in Nigeria. Among the early actions by this team of international powers is likely to be surveillance by American drones of the region where Boko Haram operates.

Surveying from the air will be easier than operating on the ground. Shekau might revel in his newly-established profile and dare the US, Britain and others to take him on. If the bait is taken, that might push more al-Qaeda sympathisers into Shekau's corner by painting him as a defender against an American invasion while boosting his stature within other international insurgent movements.

Any action against Boko Haram - presumably by Nigerian forces newly trained by the arriving Western advisers - would involve invading the Sambisa Forest Reserve, nestled in the northeast, near where Nigeria touches Cameroon, Niger and Chad. It is there that Boko Haram has its main bases, in derelict tourist huts and networks of tunnels deep in the abandoned national game reserve spread over 23,000 square miles - more than two-thirds the area of Scotland - and so untouched that it contains Nigeria's last wild elephant herds.

Kyari Mohammed, professor of history at Modibbo Adama University of Technology in the northeast Nigerian city of Yola and an expert on Boko Haram, warned: "You can't fight in the Sambisa using, let's say, drones or helicopters. You need to put in troops who are willing to fight physically on the ground. It will take some level of courage, a willingness to take some casualties."

Nigerian forces stationed in the northeast have been notably reluctant so far to enter the Sambisa. Indeed, Amnesty International revealed last Friday that the Nigerian military knew several hours in advance about the Islamists' impending April 15 night attack on the Chibok boarding school and did nothing to prevent it.

"We have gathered damning testimonies that reveal that Nigerian security forces failed to act on advance warnings about Boko Haram's raid," said Amnesty. "Poor resources and a reported fear of engaging the often better-equipped armed groups meant that reinforcements were not sent. It amounts to a gross dereliction of Nigeria's duty to protect civilians, who remain sitting ducks for such attacks."

Amnesty has also issued several previous reports alleging that the Nigerian army and police were getting away with many alleged extra-judicial executions throughout northern Nigeria. A further complication is the reality that Boko Haram fighters reside not only in the forest but also among the general population in the Shebshi Mountain range, which rises to nearly 7000 feet along the Cameroon border.It is entirely likely that the kidnapped girls have already been split among different sites and distant makeshift camps within the forest and in the mountains, said Kyari Mohammed.

He added: "The insurgents know the terrain well, better than the Nigerian military, and can melt easily into surrounding local populations that they have terrorised before. Anyone approaching is likely to be seen, and word would quickly spread to other camps."

The Boko Haram uprising is the most serious crisis to hit Nigeria since the Biafra War of the 1960s, when the Igbo people of southeastern Nigeria tried to establish a breakaway independent state in a country artificially constructed by British colonialists over territory comprising more than 250 different tribes speaking at least 500 languages.

An estimated one million civilians died in the fighting and from famine in two-and-a-half years of warfare before a ceasefire resulted in defeat for the secessionists and the reintegration of Biafra into the Nigerian Federation.

Boko Haram's revolt has already lasted longer than that of the Biafrans and could continue for many more years. It has taken countless thousands of lives.

Last week, Nigerian journalist and author Chido Onumah asked the question: Can Nigeria Survive?

"Not many countries have a second, much less a third or fourth chance to get it right," he wrote. "After 100 years, it is time we stopped seeing ourselves as Yorubas, Igbos, Hausas, Ijaws, Efiks, Ibibios, Fulanis, Tivs and everything in between. It is time we began seeing ourselves as Nigerians."

Sadly, he might have a long time to wait.