In a cosy sound-proof recording studio, housed in a decrepit building in central Tehran, Felakat lounges on a chair, surrounded by sound mixers. Sporting a tousled black shirt and a rumpled-and-spiky hairstyle – popular as "Tintin style" in the local barber's parlance – this Persian rapper could pass for a punk icon.

"I devoted my life to rap when I was just 15," says the 27-year-old whose stage name means"miserable" in Farsi. "Rap is my god." ButFelakat is well aware of the perils of indulging in rap music as a profession. The music is forbidden in Iran.

Rappers replicate American accents, indulge in obscene lyrical content and often use female leads or background voices – all symbols of Western decadence to the authorities.

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Despite the restrictions, Felakat and countless other rap musicians are the demigods of Iran's "underground" music scene – an expression that applies to any group which fails to obtain a recording license from the Culture Ministry. In a country where 70 per cent of the population is under 32, society is strongly influenced by the young.

Felakat is aware of his appeal. He coyly admits his female fanbase has "become fanatical" since the release of "Nazgol," his first hit track, themed on love and fidelity, last March. "I've had to change my mobile phone number twice," he grins.

With the introduction of satellite television in Iran in the early 1990s – also illegal – hip-hop found an explosive following and eventually the fans began to create their own version.

Another group, Zedbazi, introduced gangster rap withtheir song "Mehmooni," or "In the Club". The most famous rapper, Soroush Lashkari, who boasts the nickname Hich Kas – or Nobody – is thought of as the "father of Persian rap". And, astonishingly in a country where singing is banned for women, female rappers also dot the landscape.

The first of the female hip-hop and rap artists was Salome, who lives in Tehran and focuses on social issues such as the miseries of the war in Iraq and prostitution.

Given the restrictions, one of the main ways for Iranian rappers to get their music out both locally and globally is via the internet. Many websites – such as www.rap98.com and www.parshiphop.com – make downloading it easy. There may be fame, but there's little money in the business because of tight regulations. Most CD shop owners refuse to sell underground music, fearing raids – if caught, they face imprisonment and hefty fines. Concerts in private gatherings are sometimes cancelled because of threats from ad-hoc neighbourhood Islamic vigilantes.

In March last year, the government filtered a number of underground music websites. Last April, some rappers were incarcerated, their recording studios raided and shut down. Felakat was also arrested and later released on bail.

Mohammad Dashtgoli, of the Culture Ministry, which is responsible for vetting music "in accordance with Islam," said: "There is nothing wrong with this type of music in itself. But due to the use of obscene words rap has been categorised as illegal." But".S" has composed up to 100 Persian songs, 80 of which are rap. Only two of them have clearance from the ministry. "If we adhere to their red lines, rap will be ruined," he says. But he is hopeful that rap music will go overground one day in Iran. "The youth are the majority, and they can't ignore their aspirations," he says.