The Berbers perform in Marrakech's main tourist areas

The bands, which include boys as young as six, perform in Marrakech's most popular areas in the hope of attracting cash.

In particular they are present in the Jamaa El Fna Square, which has a long-standing reputation as a carnival centre in an increasingly conservative country.

"They do it for survival," Moroccan travel writer Yusuf Elalamy told BBC World Service's Masterpiece programme.

"It's performance, it's open-air, it's spontaneous, but they expect you to give something in return.

"The longer you stay, the more you have to pay.

"If you just have a glance then you don't have to pay, but if you stay more than a few minutes then you should pay - and if you stay longer, of course, you pay more."

'People's poetry'

The Berber tribes are such adept performers that each one can be identified by the beat of their music alone.

Melhoun musicians are usually traders and sellers

This beat comes from the tarija, a small goblet drum made of clay, which is covered with an animal skin.

The tarija forms the basis of the "sound" of Marrakech - Melhoun music, poetry in Moroccan dialect allied to traditional folk music.

It is usually associated with the makers, sellers and dealers who thrive at Marrakech's markets, such as the one in the famous Jamaa El Fna Square in the heart of the city.

One of Melhoun's most renowned performers is Mahed el Melhouny ben Omar, himself a tailor.

"Workers initiated the movement of Melhoun," Mr Ben Omar said.

"Most Melhoun composers and writers of lyrics of Melhoun are either tailors, or barbers - or sometimes sellers of vegetables, or butchers."

Melhoun was initially simply a form of poetry, but when it was combined with music it spread across Morocco very rapidly.

A Melhoun orchestra has no wind instruments, only strings and percussion.

"It emerges from the people," Mr Ben Omar said.

"It's the music, and it's also the poetry of the people.

"This is why Melhoun is not in classical Arabic."

Red city

The lyrics sometimes deal with nature, the landscape and environment, while another form is concerned with alcohol, wine and drinking.

Buildings in Marrakech are universally sandy red

But most are erotic.

One song concerns a woman named Farhar - a bold and beautiful lady, whose breasts are "like apples" and is so beautiful she is lethal - a look from her "cuts like a knife".

For many, the sound of Marrakech is as unique as the look of the city - which is almost universally a salmon pink, sandy colour.

Mr Elalamy explained that Marrakech is known throughout Morocco as simply "the red."

"All the places, all the buildings - even the buses and the cabs - are painted in the same colour," he stated.

"This is by law. It's absolutely illegal to paint in any other colour but this one.