Robert Fisk’s World: These Iranian troubadours show how music can corrupt the soul

I am old enough to remember Ruhollah Khomeini banning Mozart and Haydn

I heard them in a narrow street in north Tehran, not one of the rich villa-lined avenues we associate with the Iranian middle classes but a tired thoroughfare of overheated plane trees and shabby, two-storey offices in grey concrete.

The sound was of a scratched record, a 78-rpm rather than a 33-and-a-third – iPod addicts, please consult your elders – and when I turned to my driver, he assured me there must be some morning party up the road with an old gramophone. But I used to play the violin, and I didn't believe him. And sure enough, down the street came the troubadours.

Yes, real live troubadours in the real live Islamic Republic, two of them, hacking at a violin and beating on a "zarb" drum, the work of the classical Persian musicians, a combination – for a westerner – of gypsy and nursery melodies, a sudden revelation of 14th- and 15th-century music in a regime which aspires to the purity of the 8th. Habibullah Zendegani introduced himself very quietly – it felt that way after the rasping violin pulsating through the Italian loudspeaker on his back (hence the illusion of recorded music) – and said he was only 26 but had been playing for 15 years, inspired by that master of the Iranian violin, Bijan Mortazavi. Beside him, Ramezan Souratipour banged away happily on the drum under his arm, one of a thousand little drummers in Iran – he is 32, but a diminutive figure – whose fingers dab three to a second to Zandegani's violin.

But I am old enough to remember Ruhollah Khomeini banning Mozart and Haydn. So how do the Revolutionary Guards, praetorians of the Ayatollah's spirituality in President Ahmedinejad's oh-so-chaste republic, react to these ghosts of culture past? "I play music to earn money," Zandegani replies, a little shiftily I think. "We earn maybe $40 or $50 a day." In theory, all music must pass Iran's censorship authorities; a female singer, for example, is not allowed to sing solo lest her lone voice be too arousing for male listeners.

But music and Islam have a dodgy relationship. In Saudi Universities – and here I thank Jonas Otterbeck, Independent reader extraordinaire of Malmo University in Sweden – the most sanctimonious of students have assaulted music enthusiasts; when a professor at King Saud University, Hamzah Muzeini, condemned this brutality in the daily Al-Watan newspaper, he was convicted by a Sharia court – a ruling later overturned by King Abdullah. Yet according to journalist Rabah al-Quwai'i, some sheikhs encourage youths to burn instruments and books in public. In Saudi, I should add, Christmas carols – like all Christian religious services – are banned, except for the all-purpose "Jingle Bells". Father Christmas, I suppose, wasn't really a Christian.

It's not difficult to understand the objections to modern music and pop. Hamdi Hassan, a member of the Egyptian Assembly for the Muslim Brotherhood, complained about Ruby's first video and "the gyration of other pop stars". Incredibly, of all issues raised by the Brotherhood in the Assembly between 2000 and 2005, 80 per cent involved cultural and media issues – so much for the injustices of Palestine, Iraq and Afghanistan! In my own country of choice, Lebanon, the Ministry of Defence monitors music, according to musician Mohamed Hamza. In November, 1999, Marcel Khalife was charged with blasphemy before the Beirut courts, an outrageous infringement of cultural liberty supported by the Sunni Grand Mufti, Mohamed Kabbani. Khalife had set a verse by Palestinian poet Mahmoud Darwish to music in his album Arabic Coffeepot, but Darwish's poem contained lines from the Koran (part of verse four of Sura 12, for the uninitiated) and protesters argued that Khalife had defiled the Koran by singing it as part of a commercial song. Shiite clerics – to their great credit – defended the song-writer. He was acquitted, the Beirut judge adding that Khalife had "chanted the poem in gravity and composure that reveal a deep perception of the humanism expressed in the poem ornamented with the holy phrase." Phew.

But when Amar Hassan wanted to sing about love as well as politics in the Palestinian city of Ramallah in 2005, he was threatened before a Nablus court and his concert broken up by gunfire and the explosion of stun guns. The conflict, as Otterbeck realised in his thesis, has deep roots: between secular nationalistic music and Islamist music. In Algeria, the Islamic Armed Group made their point in lethal fashion, assassinating Berber singer Matoub Lounès.

On Al-Jazeera television, Sheikh Yusef al-Qaradawi claims there's nothing forbidden about music unless it is slanderous, sexually exciting or – and here's the rub – if it's listened to with over-enthusiasm (Islam supposedly being against all things in excess). Sufis have suggested that uneducated listeners may be stirred to sexual desire while experienced practitioners are moved by music to do God's will. The old, I suppose, know how to control themselves when they hear Mozart's "Jupiter" symphony. In Iraq, the musical scene has been bleak indeed. Shia Islamists attacked music-playing male and female students in a Basra park in 2005, killing two and wounding five others. Between 2003 and 2006, the UN found that as many as 75 Iraqi singers had been murdered; 80 per cent of the country's professional singers had left the country by the end of 2006.

I guess it's really all to do with that most jealously guarded commodity, the human soul, over which music exerts such passion. While the passion of humans should be directed towards God, music, it seems, is a diversion, even worse a perversion, the path to alcohol, adultery, murder. An Islamist internet site quotes the classical scholar Abu Hanifa who insisted that "musical instruments are the wine of the soul, and what it does to the soul is worse than what intoxicating drinks do."

Poor old Habibullah Zendegani and Ramezan Souratipour. I gave the Iranian troubadours a few Iranian rhials for their music and asked the violinist once more if he ever found himself in trouble with the Guardians of the Human Soul. "I have been playing the violin all my life," he said with a huge smile. Then, just as the couple were leaving, he turned to me with a solemn face. "Sometimes they stop us in the street," he said. "And sometimes they break our instruments."