If you work at a Starbucks in Wandsworth you might just want to take next Saturday off - else you could find yourself in the middle of an exorcism from Reverend Billy and his Church of Gospel Choir of Life After Shopping.

Preaching the values of not shopping at chain stores, Billy does not let a worldwide ban on entering the coffee shop put him off and is regularly found exorcising their cash registers as he likes to call it.

"In Norwich yesterday we exorised the demon Murdoch culture from the cash register in a Starbucks," he explained.

"A few years ago they sent us a letter banning us from all the Starbucks in the world, but according to our lawyers that's illegal.

"I was for three years legally not allowed to go within 250 yards of any Starbucks in California though.

"That was an order given by an actual judge, I'm not sure if he was a corrupt one."

As I catch up to Billy and his choir in Grantham they have just exorcised Margaret Thatcher's birthplace and in the middle of our interview Billy is dragged into an independent jewellery shop to do a blessing.

"The four people in the shop came out from behind the counter and the choir gathered around and hugged them, " he said with the choir singing in the background.

"We always make up our Gods on the spot and these were the God and Goddess of independent shops that encourage a gift economy where you get to pick out what you want and the money comes later - communities where the shoppers know the people behind the counter, everyone knows everyone.

"The wonderful aspect of this God and Goddess is to protect these little shops from product chain stores."

In case you are wondering Billy is an actual Reverend and has his own congregation of 500 people in New York, even performing marriages and baptisms.

He is over here on his first British tour promoting his anti-chain store philosophy.

"If you back away from the church of consumerism and that 70ft supermodel looking down at you from a billboard then something will happen in your soul," he said.

"Since the money markets in London and Wall Street collapsed there's a kind of seeing the light going on which we love because we were seen as eccentric before."

The choir has also been the subject of a documentary feature film made by Morgan ‘Supersize Me’ Spurlock, following them around the country as they preached.

"We end up in Disney Land jumping in front of Mickey Mouse's Christmas parade," he said.

I guess it's not just Starbucks employees that should be wary then.

Reverend Billy and the Gospel Choir of Life After Shopping, BAC, Lavender Hill, May 30, 7.30pm, £12. Call 020 7223 2223 or visit bac.org.uk.