Ties prove a knotty problem after Ahmadinejad slated by ayatollah

Iranian conservatives view the gentleman's accessory as a symbol of western decadence. It was once famously compared to a donkey's tail.

But Ahmadinejad has said no religious leader has banned the tie. He was swiftly reprimanded by a firebrand ayatollah who is normally a close ally of the hardline president.

"I say to him that many religious dignitaries believe ties should not be worn," said Ayatollah Ahmad Khatami.

He reminded Ahmadinejad that Iran's supreme leader, Ayatollah Ali Khamenei, "himself has said in a fatwa (religious edict] that wearing ties or bow ties is not permitted".

The populist and controversial Iranian president never wears a tie.

Shopkeepers say there is no written law against ties but, aware that they are taboo under Iran's strict Islamic dress code, sell them under the counter.

Two years ago, a senior official called for a ban on importing ties, insisting they were contradictory "to the nature of Iranian culture".

Whether it is clothes, hairstyles, music or children's toys, conservatives are concerned by the spread of what they regard as an American-spawned global monoculture, often described as "Westoxification".

The necktie, sported by the unpopular Shah and his ministers, was derided as a "donkey's tail" by Abolhassan Bani Sadr, the Islamic Republic's first president.

During the early years after the 1979 Islamic Revolution, ties were sometimes snipped off in the streets by zealous Revolutionary Guards.

But the necktie has made a comeback in recent years. It has been spotted with increasing frequency in the up-market restaurants and plush hotel lobbies of north Tehran, and is also worn at events such as weddings and funerals.

The tie, however, remains a fashion red line for any government official who values his job.

Ayatollah Khatami also chided Ahmadinejad for saying it was not a problem for a man to shave his beard.

"I call on Mr Ahmadinejad not to take up complicated religious questions because this weakens the government," he said.

In June, the Iranian president also aroused the wrath of several senior clerics for criticising a tough police crackdown on improperly veiled women.

Ahmadinejad's position on the dress code has been hard to fathom. Before his first term as president in 2005, he suggested he would not crack down on such personal issues, memorably declaring that he did not care about "hair sticking out of a young girl's headscarf".

But during his presidency the police have announced repeated drives on the dress code.

A crackdown this summer has been the harshest in years, with men feeling the heat as well as women.

The ministry of culture and Islamic guidance earlier this month published a guide to permissible hairstyles for men to ensure against western coiffures.