The phone rings; the number is withheld. It's Banksy. He wants to know whether I can go to Bethlehem over Christmas. He is putting on an exhibition, bringing together like-minded artists from all over the world to raise awareness of the situation in Palestine. Like the annual guerrilla art shows that have taken place in London for the past six years, it will be called "Santa's Ghetto". Two weeks later, I find myself involved in an experience that transforms my ideas about what artists can do in the face of oppression.
We are living through an exciting time for political art. I have been an artist for 40 years, and my work has always focused on political and social issues. In the 1970s, I started making photo montage work, drawing on imagery from the Vietnam War and the row over nuclear armaments (a retrospective opens at the Pump House Gallery this month). Since the build-up to the Iraq War in 2002, I have been collaborating with a younger artist, Cat Picton Phillipps, developing new techniques and using digital technology to expose the lies that led to the invasion and the subsequent humanitarian disaster.
Over this period, our work has become linked to a group of young artists who work outside the official art world. Most of them started out painting graffiti on walls. The central figure in this group is Banksy, but although he attracts most of the press coverage, he is surrounded by a growing band of talented, politically committed artists. Our associates come from Spain and Italy, the US, Britain and Palestine. Since the era of the Bush/Blair war in Iraq, this movement has become increasingly politicised, just as my generation was politicised by the war in Vietnam. These are artists who want to connect with the real world, rather than work for the market, which has more of a stranglehold on art than ever. They combine creativity with protest, insisting that art should be more than the icing on the cake for the super-rich.
We arrived in Bethlehem with four fellow artists: Blu, an Italian who has painted on walls from Bologna to Buenos Aires; Sam3, from Spain; the long-standing Banksy collaborator Paul Insect, from Britain; and Gee Vaucher, another Brit and the only other artist of my generation. The rest are all in their thirties and come from street-art backgrounds. All of them are well informed about the Middle East and came to Bethlehem to show their solidarity with the Palestinians.
Banksy had been to the West Bank a number of times to paint on the Separation Wall. He knows and understands the situation and had a team of focused, sussed people working with him. They found a disused fast-food joint in Manger Square and managed to rent it. The idea was to show a combination of western and Palestinian artists. The art was available to buy on site only, so if you wanted to get hold of the latest Banksy or any of the other artworks, you would have to travel to Bethlehem to place a bid. This was important, because Bethlehem is being starved of its tourist trade as visitors are bussed in to see the Church of the Nativity and bussed out an hour later back to Israel. All proceeds from the sale, which exceeded $1m, went to local charities.
For our contribution, Cat and I decided to print a dollar bill across 18 sheets of the Jerusalem Post, ripped through to expose images of pre-Naqba Palestine. The pictures show the richness of Palestine's history and the diversity of its culture - a sobering antidote to the stereotype of a violent, irrational people that we so often see on the news. We wanted to make the work in Bethlehem because taking finished pieces over would be difficult, given Israel's heavy and ever-changing restrictions on what and who can travel in to the Palestinian territories.
We teamed up with a group of Palestinians, who helped to get hold of materials and sort out logistics. They also gave us all a window on life in the West Bank, with looming Israeli settlements and endless checkpoints. Every night we would pile into a kebab restaurant, where we would drink and dance, arguing over and discussing that day's work. One night over dinner, the Palestinians recounted how they had been held and tortured by the Israeli authorities while they were still in their mid-teens. It was extraordinary how welcoming they were to this motley band of artists. All the privations and restrictions have only increased the Palestinians' resilience and their desire to communicate with the outside world.
Through these friends we found a commercial printing house in Hebron, which got involved in sorting out our highly unconventional printing needs. This involved printing a giant dollar across many sheets of newspaper and also making a giant print to plaster on the Separation Wall. The printers immediately committed their time and energy to the project, and ended up printing for Banksy and the other artists.
Through this process of making, the people of Bethlehem became involved in what the work was saying. After we pasted our picture on the wall, we went for tea in the cafe opposite. The cafe owner, whose business has been destroyed by the wall, told us he appreciated the statement we had plastered on to the cement that he has to stare at every day of his life.
Sticking up a poster or painting the Separation Wall in the West Bank might sound inconsequential, but these are highly practical ways to help, in contrast to the intellectual interventions prevalent in much contemporary art. They contribute to a town and a people that are having their lifeblood strangled out of them.
In this context, it is important that the work communicates directly to the Palestinian people. While there has been a move to take on contemporary issues in a direct way in the theatre, in visual art the idea still holds that if you have something to say about the world, you have to hide it behind theory and obscurity. It sometimes seems that Britain's art colleges turn out experts in camouflage, rather than fine art.
The pressure of world events is so great that it is increasingly difficult to sustain the idea of art for art's sake. Radical art and politics converge in times of crisis, and that is happening now. I know, from my experience as a tutor at the Royal College of Art and at the University of the Arts in London, that the ironies of the Nineties YBA movement are now a thing of the past. Many art students and young artists are searching for ways to make a direct connection between their awareness of how things are in the world and their own art practice.
This involves thinking about not only the form of the art itself, but also the process of making. There are many collaborations taking place across media and disciplines, and artists are looking for new methods of distribution.
Unlike in my youth, there is no organised "left" into which artists can slot, but there is a concrete wall, 425 miles long, and we can turn it into an international canvas of dissent.
"Uncertified Documents", a retrospective of work by Peter Kennard, opens at the Pump House Gallery, Battersea Park, London SW11 on 30 January. For more information, log on to: www.wandsworth.gov.uk/gallery
Four to watch
Blu burst on to the public-art scene after the success of his contributions to the "Urban Edge" show in Milan in 2005. His reputation is built on expansive, surreal, often aggressive wall and pavement murals. Though renowned for his playfulness, acclaimed pieces from 2007, such as Fantoche in Switzerland, Letter A in New York and Reclaim Your City in Berlin, have a more macabre tone.
Suleiman Mansour co-founded al-Wasiti Art Centre in east Jerusalem, which he now directs, and went on to lead the New Vision artists' group, which proved influential during the first intifada. A pioneer of resistance art, Mansour makes work that revolves around the Palestinian struggle. He was head of the League of Palestinian Artists for four years, and won the Nile Award at the 1998 Cairo Biennale as well as the Palestine Prize for the Visual Arts the same year. He is famous for using locally sourced materials, such as mud and henna, in his pieces.
Sam3 (Samuel Marín) comes from Granada in southern Spain, where his ephemeral long, black silhouettes haunt the cityscape. Famous works include his 12 Shadows project for AlterArte and the iconic Erase Yourself, a silent protest against the civic legal authorities for removing graffiti in Barcelona.
Paul Insect is a London-based ex-designer whose pioneering of "steampunk", a mixture of Gothic Victoriana and futuristic themes, has proved popular with the British arts intelligentsia. In July last year, Damien Hirst bought his entire "Bullion" show at the Lazarides Gallery in Soho. His painting Unicorn sold for an estimated £24,500 at Sotheby's last month.
Ben du Preez