As Iranians elect their sixth parliament since the 1979 Islamic revolution, the country is living through an exciting and dangerous transition. If the 20th century's only theocracy is now, at the beginning of the 21st, lurching towards a freer, more democratic system, it is to a large extent because of the dynamic, courageous Iranian press that has developed since the mid-1990s.

Journalists and editors have defied the conservatives' attempts to silence them, often braving threats and even prison sentences. Radio and television are under the control of the conservative Guide, Ayatollah Ali Khamenei, but the written press is a free-for-all, the principal battleground for the soul of Iran.

One of the main achievements of the revolution has been to raise the literacy rate from just over 50 per cent in the 1970s to 93 per cent of Iranians between the ages of six and 24. Iranians are hungry readers; there are 33 newspapers in Iran today, several with a daily circulation of 300,000 or more. Political parties are still in their infancy, so newspapers have taken on their role.

The themes raised by the independent press - freedom of opinion and association, women's rights, the rejection of violence, the need for tolerance and dialogue - coincided with the advent of the reformist President Mohamed Khatami in 1997. Mr Khatami understood that press freedom offered the fastest path to liberalisation.

But the conservatives blame the press for their ebbing power, and use their control of the judiciary to harass it. Jame'eh (Society), launched in February 1998, was the first totally independent daily newspaper. Its circulation often reached 300,000 and it mocked virtually everybody in power - except the Guide, Ayatollah Khamenei. Even that precaution did not save it. When the conservatives began demanding Jame'eh's closure in mid-1998, President Khatami's government, also irritated by its irreverence, did not object.

Ahmad Bourghani, a former vice-minister for culture who once reviewed press applications, says Iran is one of only four countries in Asia that require permits to publish a newspaper or magazine.

"The main obstacle to an independent Iranian press has not been financial, but legal and political," he told a recent issue of Middle East Report. "One must obtain a permit from the Commission for the Supervision of the Media, which is composed of one representative each from the Ministry of Culture, the Judiciary, the Parliament, the press and the university community."

Despite the red tape, Jame'eh kept resurrecting itself. Its editors launched a new daily, Tous, on the very day Jame'eh was banned. Tous survived for one week before it too was shut down and its editors beaten up. The publisher restyled it as Aftab-e-emrooz (Today's Sun). Tous was allowed to reappear; then both papers were shut down and their editors jailed for several weeks.

The Jame'eh group started a fourth newspaper, Neshat (Joy) a year ago. It survived for nine months, until it published two articles criticising the death penalty and the "eye-for-an-eye, tooth-for-a-tooth" punishments still in force in Iran. Neshat's editor-in-chief, Mashallah Shamsolvaezin, was put on trial for "anti-Islamic propaganda" and sentenced to three years in prison.

He is free while his appeal is considered. "There is freedom of expression in Iran," Mr Shamsolvaezin says. "But no freedom after expression."

On July 7th, 1999, the conservative parliament passed a press law creating even greater censorship. It moved jurisdiction for press offences from a special press court to revolutionary courts, which try political and criminal cases. Henceforward, the law said, journalists would be required to reveal their sources, and the publisher would no longer be the only one held responsible for content. Photographers, editors and journalists would share blame. The passing of the law - and the banning of the daily Salam (Hello) at the same time - sparked a week of the worst student riots since the revolution. It has not yet been enforced, perhaps because the conservatives, like their reformist opponents, are constantly testing the limits of how far they can go.

Salam's banning was itself the consequence of daring investigative reporting by two other reformist or Islamic left newspapers, Khordad (the third month of the Muslim calendar, when President Khatami was elected) and Sobh-e-emrooz (Today's Dawn).

At the end of 1998, these papers reported that members of the conservative-run Intelligence Ministry were behind a spate of assassinations of intellectuals and political leaders. President Khatami confirmed the veracity of their reports. The former vice-minister of intelligence, Said Emami, was sent to prison, where he allegedly committed suicide.

Salam's sin was to reveal, the day before the parliamentary vote on the new press law, that it had been drafted by none other than Said Emami, the dead vice-minister. Not only was Salam shut down for five years, its editor, Ayatollah Khoeiniha (who once organised the seizure of the US embassy in Tehran), was forbidden from any press-related activity for three years.

The one red line most Iranians know better than to cross is criticism of the Guide, Ayatollah Khamenei. The leader of the Islamic Association of Students, Heshma tollah Tabarzeddi, was arrested in June 1999 after he suggested the Guide should be elected through a direct ballot for a limited period and that his responsibilities be better defined.

During his November 1999 trial for "anti-Islamic propaganda", the former Interior Minister and publisher of Khordad newsaper, Abdullah Nouri, shocked the court by saying the same thing. "Ali Khamenei is not a `guide'," Mr Nouri said. "He is just an administrator of the revolution who must be subject to laws, like everyone else." Other Nouri heresies included his contention that the United States is "the most important actor on the international scene, whom Iran will not be able to ignore forever."

Mr Nouri's trial statements were stunning, coming as they did from a member of the clergy and a close friend of President Khatami. He was sentenced to five years in prison, and thus prevented from leading the reformers' campaign in the parliamentary election.

Khordad was banned.

The struggle between censoring conservatives and free-minded reformers continues. As the parliamentary election campaign got under way this month, Nik Ahangh-Kosar, the cartoonist for Azad newspaper, was arrested and taken to Evin prison.

He had drawn two caricatures of the prominent conservative cleric Ayatollah Mohamed Taqi Mesbah-Yazdi, who frequently attacks reformers in his sermons and has implied that journalists working for reformist newspapers are paid by the CIA. One drawing showed Mesbah-Yazdi as a crocodile, weeping at the threats of "mercenary progressive writers".

In the other, a man wielding a club demands that a pen-bearing journalist "confess where he hid his dollars". The cartoons sparked an anti-press demonstration by hundreds of mullahs in the holy city of Qom.

If the final election count shows that President Khatami's Participation Front has wrested parliament from the conservatives, the work of Iranian journalists will become easier. Regardless of the outcome, the new Iran emerging now, 21 years after the revolution, will not be built without difficulties - but hopefully without violence. As Mashallah Shamsolvaezin, the Neshat editor who is appealing his prison sentence, says, "democracy in Iran is a minefield for which we haven't got a map."