Pakistani opposition leader Benazir Bhutto knew very well the risks she ran when she decided to wage a public campaign for the restoration of democracy.

Hours after she returned home in October after eight years of self-imposed exile, a suicide bomber killed nearly 150 people in an attack targeting her motorcade in the streets of Karachi.

The attack followed threats by militants linked to al Qaeda, angered by Bhutto?s support for Washington?s war on terrorism. ?They might try to assassinate me,? Bhutto had told the pan-Arab Asharq al-Awsat newspaper in an interview before she set out to return to Pakistan. ?I have prepared my family and my loved ones for any possibility.?

Despite being in the wilderness for most of the past decade, the tall, stately Bhutto remained one of the most recognisable female politicians in the world.

In 1986, a vast sea of supporters had welcomed her home as she came back to challenge a military dictator who had executed her father, deposed Prime Minister Zulfikar Ali Bhutto, seven years earlier.

Bhutto became the first female Prime Minister in the Muslim world when she was elected in 1988 at the age of 35. She was deposed in 1990, re-elected in 1993, and ousted again in 1996 amid charges of corruption and mismanagement.

She said the charges were politically motivated but in 1999 chose to stay in exile rather than face them.

After more years spent abroad, Bhutto, 54, flew back again in October to lead her Pakistan People?s Party (PPP) into national elections. This time, though, rather than confronting a military ruler, she was hoping to work with army chief and president Pervez Musharraf for a peaceful transition to civilian rule.

Western allies saw their cooperation as the best way to sustain the nuclear-armed country?s efforts against terrorism.

But after Musharraf imposed a state of emergency in early November, Bhutto angrily protested and redoubled her calls for the president to quit the army and hold free elections.

Even when, under worldwide pressure, Musharraf resigned from the military in late November, Bhutto and rival party politician Nawaz Sharif continued to keep him at arm?s length, warning of attempts to rig the coming polls.

Both of her brothers died in mysterious circumstances and she said al Qaeda assassins had tried to kill her several times in the 1990s. Intelligence reports have said al Qaeda, the Taliban and Pakistani jihadi groups have sent suicide bombers after her.

Bhutto had said that if she were in power she would allow US forces to hit al Qaeda targets in Pakistani territory, if Pakistan?s own forces were unable to carry out an attack.

Bhutto, whose first name means ?unique?, was born in 1953 into a wealthy landowning family. The first of four children, she was educated at a Christian mission school in Karachi, and then at Harvard and Oxford universities.

The daughter of Pakistan?s first popularly elected leader, her mission began in 1977 when army chief Mohammad Zia-ul-Haq overthrew him. Twenty-one months later it became a blood feud when Zulfikar was hanged after a controversial trial.

For years Bhutto fought against Zia without success. She and her mother, Nusrat, were in and out of prison until she was allowed to go abroad for medical treatment in 1984.

In August 1988, Zia was killed in an air crash. Bhutto?s election victory later that year was welcomed worldwide as the advent of democracy in Pakistan. But many in the powerful security services distrusted her, and President Ghulam Ishaq Khan sacked her after 20 months, accusing her of presiding over large-scale corruption.

She accused the establishment of rigging elections three months later to bring their protege, Nawaz Sharif, to power. Bhutto clawed her way back in 1993 but was again kicked out of power on charges of corruption and misrule.

Asif Ali Zardari, the businessman Bhutto wed in an arranged marriage in 1987, was seen as her greatest liability.

He was released on bail after eight years in prison in 2004. The deal under which Bhutto returned home in October also erased charges against him.

Pakistan on the brink of civil war

This assassination has thrown Pakistan into one of the worst crises in its 60-year history, raising the spectre of widespread civil unrest and the cancellation of elections.

Analysts say President Pervez Musharraf, who stepped down as army chief of the nuclear-armed country two weeks ago under intense international pressure, is likely to seize the moment to reimpose emergency rule and cancel, or at least postpone, elections scheduled for January 8. ?It is fair to assume now that elections cannot go ahead,? said Farzana Shaikh, an expert on Pakistan and an associate fellow at the Chatham House analysis group in London. ?The electoral process has been stopped dead in its tracks. I think there is a very real possibility that Musharraf will decide that the situation has got out of control and that he needs to impose emergency rule again?. She said Pakistan, a key US ally in the battle against al Qaeda and the Taliban in Afghanistan, was entering ?uncharted waters?, which could lead to instability in a region that has seen three wars fought between Pakistan and its nuclear-armed neighbour India.

?This is not the first crisis Pakistan has faced since its inception in 1947, but I would be inclined to say that it is the worst convergence of crises we have seen,? Shaikh said.

While Islamic hardliners, including members of the Taliban and al Qaeda, both of which operate in Pakistan, have been named as possible perpetrators of the attack, analysts said Bhutto?s political opponents and those close to Musharraf?s political party could not be ruled out of suspicion. ?It?s going to be very difficult to establish the truth of who was behind this,? said M.J. Gohel, the executive director of the Asia-Pacific Foundation, a security and intelligence think-tank in London.

?As well as the Taliban and al Qaeda elements, there are many other candidates ? there are elements within the military and elements within the intelligence services, which never had a good relationship with Bhutto. There are of course political opponents as well ? she had a lot of enemies within Pakistan as everyone knows.?

Shaikh pointed to the fact that Bhutto was killed in Rawalpindi, which is a long way from the North West Frontier province where Islamic militants usually operate. ?That will raise fears that there was some level of official negligence that permitted this attack to go ahead,? she said. ?These sorts of events are going to raise very serious concerns about whether there was some sort of official connivance.?

Bhutto?s campaign managers have complained frequently that not enough was being done at a national level to protect her.

She narrowly escaped assassination on her return from exile in October when a suicide bomber blew up her campaign bus, killing 139 people. Gohel said that as well as the domestic repercussions of Bhutto?s assassination ? angry supporters clashed with security forces in the hours since her death ? there were widespread international concerns as well.

?The ramifications are enormous,? he said. ?There will now be more violence and if Musharraf imposes another state of emergency there could be further crackdowns and protests. We are looking at a political vacuum if the elections don?t take place. The radical Islamists could really start occupying that vaccuum and operating from within it. Pakistan is a country that is home to al Qaeda and the Taliban and is also obviously home to nuclear weapons and long range missiles... all of which have repercussions for the West and the world.?

April 1979: is imprisoned just before her father, Zulfiqar Ali Bhutto, is executed by General Zia ul Huq. She is sentenced to five years in jail.

1984: is allowed to leave for London for health reasons after spending most of her years in prison in solitary confinement. She reorganises her father?s Pakistan People's Party (PPP) in London and takes over its leadership.

April 1986 : returns from exile in London and holds political rallies, attracting massive crowds.

December 6, 1988: becomes the first woman Prime Minister of a Muslim nation after winning parliamentary elections.

August 6, 1990: Bhutto government dismissed by President Ghulam Ishaq Khan on grounds of corruption charges against her and husband Asif Zardari. Her political opponent Nawaz Sharif of the Pakistan Muslim League is made Prime Minister.

July 1993: President Ghulam Ishaq Khan dismisses Sharif as Prime Minister, also on grounds of alleged corruption.

October 19, 1993: Bhutto takes oath for a second term as Prime Minister after elections in which no party is a clear winner. She takes the support of smaller parties.

September 1996: Murtaza Bhutto, Benazir's younger brother, is shot dead by policemen along with six of his political workers.

November 5, 1996: Bhutto government dismissed again ? this time by President Farooq Leghari, not only on charges of corruption but also of carrying out staged killings.

February 1997: Sharif becomes Prime Minister again after his PML convincingly wins general elections.

April 14, 1999: Bhutto and Zardari found guilty of corruption charges involving a Swiss company, while she is out of the country. Zardari goes to jail, and Bhutto remains in self-exile.

May 1999: Pakistani troops and militants occupy positions in the Kargil area of Kashmir. Strains emerge between Sharif and Musharraf after international condemnation led by the US.

October 1999: Sharif sacks Musharraf, but the general hits back by leading an army coup against him and taking control of administration.

August 2000: Musharraf bars Bhutto and Sharif from active politics.

December 2000: Sharif goes into exile.

July 2002: Court sentences Bhutto (in absentia) to three years in prison on corruption charges.

July 2003: A Swiss court convicts Bhutto and Zardari for money laundering. Given jail sentences and fined.

November 2003: Sentence overturned by a higher court.

November 2004: Zardari released from prison in Pakistan.

March 2005: PPP says it is increasing contact with Musharraf.

October 5, 2007: Musharraf signs a corruption amnesty against Bhutto.

October 6, 2007: Musharraf wins presidential election.

Oct 18, 2007: Bhutto returns to Pakistan from eight years in self-exile.

November 15, 2007: Musharraf's five-year presidential term and the term of the sitting parliament expires.

January 8, 2008: The date for parliamentary elections ? that are now in doubt after Bhutto's assassination.

WORLD SHOCKED

World leaders voiced outrage and expressed fears for the fate of the nuclear-armed state.

■ US President George W. Bush condemned the killing as a ?cowardly act? and urged Pakistanis to press ahead with a planned national election.

■ Russia?s top Asia diplomat said the assassination would ?trigger a wave of terrorism?.

■ British Prime Minister Gordon Brown said Bhutto had risked everything to try and bring democracy to her country, of which Britain used to be the colonial ruler.

?The terrorists must not be allowed to kill democracy in Pakistan,? he said.

■ ?The subcontinent has lost an outstanding leader who worked for democracy and reconciliation in her country,? said Prime Minister Manmohan Singh of India, Pakistan?s giant neighbour and nuclear rival. ?The manner of her going is a reminder of the common dangers that our region faces from cowardly acts of terrorism and of the need to eradicate this dangerous threat.?

■ French President Nicolas Sarkozy called the killing odious.

?France, like the European Union, is particularly attached to stability and democracy in Pakistan,? he said in a letter to Pakistan?s President Pervez Musharraf.

■ UN Secretary-General Ban Ki-moon said the assassination was a ?heinous crime? and an ?assault on stability? in Pakistan. The UN Security Council began consultations on the killing.

■ Jose Manuel Barroso, president of the European Union?s executive arm, the European Commission, said it was ?an attack against democracy and against Pakistan?.

■ ?It is a criminal act and is strongly condemned,? Iranian Foreign Ministry spokesman Mohammad Ali Hosseini told state television in Pakistan?s neighbour. ?What Pakistan strongly needs now is calmness and the return of stability.?

■ A Vatican spokesman said Pope Benedict had been informed, adding: ?It is difficult to see any glimmer of hope, peace, reconciliation in this country.?

SHARIF SAYS TO BOYCOTT JANUARY ELECTION

Pakistani opposition leader and former Prime Minister Nawaz Sharif said yesterday his party would boycott the January 8 general election. ?The PML (N) is boycotting the election after the assassination of Benazir Bhutto,? Sharif told a news conference in Islamabad, referring to his party.

?Free elections are not possible in the presence of Musharraf,? he said referring to President Pervez Musharraf. ?Musharraf is the root cause of all problems.? Old rivals Bhutto, also a former Prime Minister, and Sharif had recently cooperated in their opposition to Musharraf.