Updated

London buses have God on their side — but not for long, if atheists have their way.

The sides of some of London's red buses will soon carry ads asserting there is "probably no God," as nonbelievers fight what they say is the preferential treatment given to religion in British society.

Organizers of a campaign to raise funds for the ads said Wednesday they received more than $113,000 in donations, almost seven times their target, in the hours since they launched the project on a charity Web site. Supporters include Oxford University biologist Richard Dawkins, who donated $9,000.

The money will be used to place posters on 30 buses carrying the slogan "There's probably no God. Now stop worrying and enjoy your life." The plan was to run the ads for four weeks starting in January, but so much money has been raised that the project may be expanded.

"A lot of people say trying to organize atheists is like herding cats. The last couple of days shows that is not true," said comedy writer Ariane Sherine, who started the campaign.

While most London buses carry posters for shops or Hollywood movies, Christian churches and Muslim groups have bought bus-side ad space in the past.

Sherine came up with the idea after seeing a series of Christian posters on London buses. She said she visited the Web site promoted on one ad and found it told nonbelievers they would spend eternity in torment in hell.

"I thought it would be a really positive thing to counter that by putting forward a much happier and more upbeat advert, saying 'Don't worry, you're not going to hell,'" said Sherine, 28. "Atheists believe this is the only life we have, and we should enjoy it."

The British Humanist Association, which is administering the fundraising drive, said it had been so successful the campaign might spread to other cities including Manchester and Edinburgh.

Most Britons identify themselves as Christians, but few attend church regularly, and public figures rarely talk about their beliefs. Former Prime Minister Tony Blair was rare among politicians in speaking openly about his Christian faith.

Dawkins, author of the best-selling atheist manifesto "The God Delusion," said that religion nonetheless held a privileged position in society.

"Religious organizations have an automatic tax-free charitable status," he said. "Bishops sit in the House of Lords automatically. Religious leaders get preferential treatment on all sorts of commissions.

"This campaign to put alternative slogans on London buses will make people think — and thinking is anathema to religion."

Dawkins said that as an atheist he "wasn't wild" about the ad's assertion that there was "probably" no God.

Sherine said the word was included to ensure the posters didn't breach transit advertising regulations, which stipulate ads should not offend religious people.

Few believers appeared offended by the campaign, although most doubted it would work.

"I think people will ask themselves, 'On what basis can they make that statement?" said Inayat Bunglawala of the Muslim Council of Britain. "So it will get people thinking, so in that sense it can only be good."

Ad agency CBS Outdoor, which manages advertising on many London buses, said it had approved the atheist campaign.

Sales and marketing director Tim Bleakley said "our decision to take an ad that promotes God, or one that promotes no God, is based on commercial terms, as long as the advertising copy itself does not breach U.K. advertising standards."

The Rev. Jenny Ellis, spirituality and discipleship officer for the Methodist Church, welcomed the ads.

"This campaign will be a good thing if it gets people to engage with the deepest questions of life," she said.

The religious think tank Theos said it had donated $82 to the campaign, on the grounds that the ads were so bad they would probably attract people to religion.

"It tells people to 'stop worrying,' which is hardly going to be a great comfort for those who are concerned about losing jobs or homes in the recession," said Theos director Paul Woolley.

"Stunts like this demonstrate how militant atheists are often great adverts for Christianity."