They're enormous. Unmissable. Murals that burst bright shots of red that ebb to whiteish pink, or splashes of lime that drain to deep green, sky blue that flashes light blue. Decorated with crazy, curved letters in aerosol paints. “Remember God,” they say, or “Feed the Poor.” Perhaps simply “Peace” or “Thirst for change.” Writing in Arabic above or below.

You’ll spot them on a wall in Burnley, or a siding in the Bronx.

This is Islamic graffiti, vibrant street art that fuses Koranic calligraphy with the shapes and colours of pop art, a style virtually invented by Mohammed Ali, 30, from Birmingham.

Ali’s on a mission – to promote dialogue, even world peace through graffiti with a spiritual message.

“You won’t find a single young person – black, white, Muslim, Christian or Jew whose eyes don’t light up when you mention graffiti,” says Ali, who won the South Bank Show's Arts' Council Diversity Award this January.

Influenced by his Muslim faith, Ali doesn't seek to "preach" , choosing words from the Koran or the Hadith - the sayings of the Prophet - he thinks accessible to "everyone of any faith or none."

In Melbourne, for instance, Ali illustrated a graffiti on saving water – a message particularly pertinent to drought-stricken Oz – with a saying from the Prophet Mohammad: “What I'm saying is that rain ultimately comes from God, a 1,400 year old message that’s still relevant.”

He does think carefully about where he places the sacred verses. "If they are going to appear on a wall, I would paint them high up to avoid the possibility of people painting over them or urinating on them."

An illegal tagger as a teen, Ali reverted to Islam, the faith of his Bangladeshi-born family while a student at de Montfort University, Leicester.

The breakthrough was realising that “Islam is not just about sitting in a room meditating all day long” he says.

“A lot of people in the Muslim community who become devout in religion reject and abandon everything from the past, especially if it is seen as too Western,” he explains. “I felt graffiti didn’t conflict with faith. Writing and decorating fit perfectly with Islamic art.”

Isn’t all art haram – forbidden – for Muslims? “No,” says Ali. “The Prophet Mohammad taught that figurative depiction - idols as symbols of worship - should be avoided. But he never discouraged creative expression.”

Visit a mosque, and you’ll see Islamic calligraphy decorating the dome, he explains. Plus many Muslims have wall hangings with Islamic verses in their homes. “Many Muslims are quite oblivious to this,” Ali says. “Yet for Muslims creative expression is about decorating the word of God.”

His art bridges a culture gap, Ali feels, between Islamic culture and the West. He has been invited to create graffiti murals and give talks to schools in America, Australia and Canada to date. Generally the response is positive. Occasionally, it is misunderstood.

In Chicago, which he visited on an Arts Council funded tour in 2005, he was asked to stop painting a mural by local fireman.

They assumed the Arabic letters he had begun to paint represented the toppling of the Twin Towers. Ali " tried to talk to them" but they said " We lost so many colleagues on September 11, and now we have to see this wall every day.” At the end of the day, it was not my community and I hadn’t come to ignite the issue, though I am sad the wall is unpainted. But I am trying to bring people together, not tear them apart," he says.

He is convinced the much vaunted "clash of civilisations" is a myth. Keen to reassure young Muslims that an Islamic presence in Europe is nothing new, he is bringing a group of young British Muslims to Southern Spain, to introduce them to the region's medieval Moorish art.

They will visit, amongst other cities, Granada, where the streets Ali notes, are filled with artists reproducing the Alhambra in watercolour. He plans to introduce a more unusual sight: “We are going to be there, doing a reproduction of the Alhambra with spray paints,” Ali grins

Mohammed Ali: South Bank Show, January 2009

Aerosol Arabic