Saturday is buy nothing day. A global attempt by anti-capitalists to break the tyranny of the till. Jessica Berens joins the Reverend Billy to see how 'Guerilla theatrics' are enlightening unsuspecting consumers

Observer

This is the second 'action' of the week. The first time the Reverend stood in the middle of Starbucks and launched into a loud sermon. ' You are trapped in a bubble of bourgeois safety !' he shouted. It took 90 seconds for the manager to threaten to call the police.

I nearly died of fright. I thought there would be platoons of Darth Vader policemen, and we would be batoned into outpatients. There would be pro-bono lawyers and holding cells and, despite Naomi Klein, that would be it. Jesus, I don't like speaking, let alone agitating. Keep your head down, resist from the shadows, that's my calling, but now the Reverend is leading us towards the Light.

Over the last two years, Reverend Billy and the Church of Stop Shopping have tormented Starbucks by using them as stages for dramatic protests. The Church has thus earned an honoured place in the realm of guerrilla theatrics, where non-violent provocation (or 'culture jamming') has come to take many forms - from the Radical Cheerleaders of Canada, to the puppets of Art and Revolution, to the insanely intelligent 'Yesmen', whose weirdly dressed subversives appear as WTO representatives and give bizarre speeches at free-trade conferences in order to illuminate the inhumane policies that lie within economic theory.

Culture jamming is now both sophisticated and effective. This is thanks, in part, to the Vancouver-based Kalle Lasn and his 'Adbusters' website. A typical Adbusters 'subvertisement' is designed like a Calvin Klein image and shows a model throwing up in the loo in order to convey the close relationship between the low body image of women and the morbid cadavers sold as beauty. Adbusters also launched Buy Nothing Day, which is being held next Saturday, 30 November, which has grown into a worldwide culture jammers event.

After three days with the Church, I am a calm and converted jammer. I could put a flower in a soldier's rifle and shout about the coffee crisis no holds barred. And the coffee trade is in a crisis. Check out the Oxfam reports on the discrepancy between the decreasing price of the bean and the increasing wealth of companies like Nestlé. Result? Cyclical poverty of some 25m farmers' families. And in America, the Organic Consumers Campaign is targeting Starbucks' use of milk made by cows treated with recombinant Bovine Growth Hormone.

Behold He cometh with great swelling words. The Reverend and his wife Savitri have been invited to teach Michigan arts students about the possibilities of taking protest theatre into public spaces and using performance as a means to activism. That is the Reverend's realm - the effective conjunction of politics and street drama. Classes, held in Room 2528 of the Frieze Building, have lured Emily with pink hair, and Nathaniel with blue - kids in sneakers and Michigan logos, sitting at little desks asking pointed questions about the hypocrisies that cunningly hide in the principles of 'ethical consumerism'.

'Yes,' the Reverend has been forced to confess. 'I have bought a Gap shirt from the Salvation Army thrift store. I ripped out the label to remove the guilt.'

And yes, he does drink coffee, triple lattes, actually, in cups the size of waste paper bins. It's not the coffee he objects to, it's the 'fascism of convenience' that corrodes the individualism of communities and kills neighbourhood businesses.

A loud witchy cackle has occasionally erupted from the front of the classroom. It belongs to a small woman with crew-cut grey hair, a Hello Kitty watch and a badge the size of a shield saying No To War in Iraq. Holly Hughes is an energetic provocateur with a radical background in lesbian performance. Employed by the university faculty as a visiting professor to teach art, she is responsible for launching the Reverend on to the campus to teach a theatre course that will end in a multi-media performance enacted by students.

'Most students have little experience of challenging art,' she observes.'The critique of consumerism is a new idea to them. But I wanted them to learn that a modern art experience isn't necessarily about comfort and entertainment.'

Today, Wednesday, the action has been planned in Biro on pieces of paper as a military strategy that shows where the doors of Starbucks are, the position of the till and so on. Savitri, leading the charge, has told us that, 'performing in a public space is a completely radical experience. It can change your life.'

Five of us will take photographs in order to camouflage and support The Observer photographer, commissioned to portray the Reverend in full manifestation. Despite the faux boho atmosphere, the digitally remastered jazz music, the cozee-glo fires, the comfy chairs, and the ersatz echoes of beat dissidence, gainsay is not desired. Nevertheless, the organisation has been the target of disapproval since 1999 when the first brick was lobbed at its window in Seattle's anti-capitalist 'battle' against the World Trade Organisation.

We enter one after the other, the Reverend last. Quiet, but determined, he goes from seat to seat. He 'blesses' the customers and attempts to convert them as they sit with their Sumatran blends and books and laptops. They can't get away, they can only exist in the eternal seconds that are the hours of being entrapped by a man moving in a Billy Graham loop. Is he the representative of the Lord, or isn't he?

'You know what?' says one girl from the depths of her armchair. 'I am so comfortable right now, that it is really hard to take listening to you telling me the truth.'

Then he stands up, this creation of enragement, arms waving, all wild charisma and dogged belief, preaching his gospel like the orange-faced southern preachers who appear on American TV at 3am. 'I want you to think about giving your business to this company!' he proclaims. 'I want you to think about the milk they use and about the coffee farmers still living in poverty.'

This morning he has more time to preach. The manager, confused by the five photographers, puts his hand over the video camera, but he is on to a loser. There are too many other lenses clicking. The Reverend comes to a close and we all amble, unmolested, into the crisp autumn sunlight. The pleased evangelist stands on the pavement and smokes a post-action cigarette.

'Well,' he says. 'At least I'm not in jail ...'

Alleluia!

He is six foot tall, though he looks bigger because of the hair. He is 47, and is, in fact, a person named William Talen, from Holland, Michigan, of a straight, strict Dutch Calvinist background where 'God was a Republican'. The idea of a skin-burning Hell was so indoctrinated that William was afraid to allow his imagination to wonder in case the flames spontaneously ignited and his trousers caught fire.

His father is a banker and has never been very pleased with him. When Bill led protests against Disney and paraded around with Mickey Mouse pinned on to a crucifix, a therapist told him that Mickey was his father. And that was what it was all about. Born in an era of protest, Bill became a hippy wannabe. Agitation came very easily to him and was as much a part of his dramatic personality as a product of his politics. 'I read James Joyce and took the sinful trail,' he remembers.

As a teenager, he was a runaway and his father had him arrested. Later, objecting to a family decision to spend the evening watching home-videos, Bill set up an alternative entertainment next door by playing Jimi Hendrix at full volume. When various cousins defected to his side, there was a loud kerfuffle and Uncle Jerry called the police.

'He is,' says Savitri, 'completely unemployable.'

'I once sold encyclopedias,' is the rejoinder. 'I didn't get fired from that!'

Savitri Durkee, dark and fearless, from New Mexico, enjoys a career as a director of fringe theatre. She has a gleam in her eye and a small video camera constantly in her hand. She met Bill in a lift at a New York theatre in which they both worked. He is a bit like her father, she says, who is also prone to explosions of anger and who is also a maverick: 'My father has spent eight years translating the Koran specifically for people in prison.'

Bill and Savitri were married six months ago, and they are a cool team. She possesses the management skills of an adept organiser, and a relentless curiosity which harnesses the thunder of her husband and helps to channel it into a disciplined offensive.

It is difficult to live to the principles they have set themselves, where all purchases must be questioned and remuneration is not a given. Like many of us, Savitri is unnerved. By rubbish and additives and plastic. By ecocide. By acquisitive monster-children with TV opinions. By the obese forms that lurk in malls, haunting symbols of consumerism gone (free trade) bananas. 'It is crucial to wake people up,' she says. 'If enough people cared, things would change.'

Bill claims he cannot remember much of his twenties, but there was a lot of hitch-hiking across state lines and, somewhere around this time, he took up body building and creative writing. He ended up, inevitably, in San Francisco, where he was at home producing fringe theatre, in particular, as founder of Life on the Water. Then the backers pulled the funding and he was out of a job. At the age of 40, all semblance of middle-class structure destroyed, he found himself waiting on tables in New York.

'I was living in Hell's Kitchen,' he says. 'I was drunk and sad and walking into walls. Then I asked myself, where is theatre? It certainly isn't on Broadway. I looked at the sidewalk preachers in Times Square - everyone was ignoring them and they looked like the creeps who had raised me - but their theatre was very strong. I bought a little pulpit from a Christian supply shop and I dyed my hair. I would go out on to the sidewalks and just shout.'

As Bill Talen turned into the Reverend Billy - somewhere between an alter ego and a personality disorder - he was a natural hero in New York, where burgeoning objection to multi-national power was melding into the worldwide anti-capitalism movement.

Disney was one of his first stages. A memorable 'performance' in 1998 involved a 'cell phone opera' where 'customers' moved through the Disney mega-store in New York speaking into their mobiles, saying things like, 'Oh, I don't think we should buy him that, honey. They use sweatshops to make this stuff, you know!' Then the Reverend stood up and announced that Mickey Mouse was the Antichrist.

Walt's wonderland closed down in the ensuing chaos, while the Reverend and his apostles were hauled off to the nearest precinct.

The Reverend's spiritual home is the Lower East Side of Manhattan and, in particular, St Mark's Church. Here the Church of Stop Shopping stage gatherings, complete with gospel singers. During their services the congregation often throw away their credit cards and the Reverend preaches his message in sepulchral tones.

'We are drowning in a sea of identical details, my children. It gets to the point where I don't know where I am. And when I don't know where I am, I don't know who I am and I am in the pit of hell!'

Their most recent gathering featured the writer Kurt Vonnegut, who was canonised as their saint. 'He was in the front row,' Bill remembers fondly. 'It was great to have him.'

Over the years there have been a lot of arrests, but there has also been an Obie (awarded for achievements in off-Broadway productions) and some good reviews. 'This is a much savvier kind of radicalism than anything you have seen in the 60s,' said one New York theatre critic. 'You don't expect this sort of community cohesiveness in acts of civil disobedience in this day and age.'

Now there is a TV show in development, and the Reverend has been commissioned to write a book.

There are some enlightened vendees who will find it easy to fall in with the Reverend's anti-consumerist argument and buy nothing on Buy Nothing Day. They are probably the people who are wondering why - after they have bought the car, the shoes and the cream - they still feel old and unhappy and afraid. But independent thinkers are still in the minority and the anti-consumerist cause is still fraught with insoluble conundrums as transnational agribusiness and globalised brands argue that they provide affordable food and essential jobs. A recent Newsweek article, written at a time of declining confidence, described consumers as 'heroes' uncowed by terrorism and decimated stock prices.

Meanwhile, Starbucks has apparently satisfied most of its customers with PR pamphlets about its involvement with Fair Trade, though detractors say that this powerful organisation could do much more to redress the imbalances that are causing widespread misery within the coffee trade. The company enjoys an annual revenue of $2.65bn and plans to open another 100 cafes in America, bringing the number up to more than 5,000 worldwide.

The Reverend is aware of all this, but he has no intention of surrendering. 'I believe that the dominance of our personal lives by products and by the delivery systems of those products - the imagery, the ads, the celebrities - is so remarkably complete right now we simply must have nothing short of a revolution. We must practise backing away from the product. We must open up that space between ourselves and the product in order to remember how unique we are and to remember how much we can do without the supervision of these products.' Amen.