Mr Anwar was sentenced to six years' imprisonment in April 1999 after a five-and-a-half month trial - the longest in Malaysian history.

The trial and subsequent verdict were accompanied by street protests and nationwide publicity. It was a spectacular fall from grace for a man once seen as Dr Mahathir's chosen political heir.

Dr Mahathir sacked his young protege in September 1998 after months of disagreement over economic policy. As finance minister, Mr Anwar had strongly opposed Dr Mahathir's increasingly virulent attacks against western financiers in the wake of the Asian economic crisis.

Shortly after he was arrested Mr Anwar appeared in court with a black eye - the result of a beating by police. Pictures of the man who had once seemed destined to become prime minister limping into court sent shockwaves around the world.

Lurid accusations

Anwar Ibrahim: "This is part of a larger political conspiracy" (September 1998)

During his trial state prosecutors accused Mr Anwar of sexual misconduct and corruption, arguing that he was an adulterer who had abused his office to cover his tracks.

Mr Anwar denied the charges, maintaining from the outset that he was the victim of a high-level conspiracy.

The trial saw lurid and highly public accusations about Mr Anwar's sexual behaviour, with prosecutors at one stage producing a mattress in court which they said showed semen stains from his alleged sexual misconduct.

Halfway through the trial the prosecution re-wrote the charges so that they no longer had to prove any of the alleged sexual liaisons took place - merely that he abused his office in an effort to cover them up.

Anwar Ibrahim: "I believe in a civil society" (September 1998)

The trial and sentencing galvanised political opposition in Malaysia, splitting the majority Malay community, and bringing people out onto the streets in unprecedented protests against Dr Mahathir's 18-year rule.

Supporters of Mr Anwar, both in Malaysia and overseas, communicated through the Internet about what became the opposition's cause celebre.

When Mr Anwar was finally sent to prison after months of highly-charged court proceedings, there were riots by his supporters on the streets of Kuala Lumpur.

Trial number two

In poor health, he now faces a second trial, which began in June, this time on sodomy charges.

Mahathir Mohamad: Due to testify against Mr Anwar

But hours ahead of Dr Mahathir's announcement on 10 November calling snap elections, proceedings were abruptly suspended after the presiding judge complained of a backache. There was no immediate word on when the trial would resume.

Dr Mahathir himself had been due to testify against his former colleague, but observers point out that a showdown between the prime minister and Mr Anwar in court might not have been good pre-election publicity.

Anwar Ibrahim: "I demand justice" (September 1998)

Malaysia's Election Commission has been unclear as to whether Mr Anwar - Dr Mahathir's main political rival - can contest the elections from behind bars.

In the months since the trial, Malaysia's socialist and Islamic opposition parties have come together to unveil a joint election manifesto promising political and economic reforms. They accuse the government of cronyism and nepotism.

Mr Anwar's wife, Wan Azizah, who has formed the National Justice Party has been the driving force behind the opposition's electoral coalition.

She has named her husband and the coalition's candidate for prime minister in the event of a surprise win.

Dr Mahathir, meanwhile has been dismissive of the political controversy surrounding Mr Anwar. Only foreigners, he says, thought the Anwar issue was important.