The advertising campaign is being planned and part funded by the British Humanist Association (BHA), which has already raised £15,300 towards costs. "God Delusion" author and prominent atheist Professor Richard Dawkins has offered to help finance the campaign.
The campaign will run posters on 30 of London's bendy buses with the slogan, 'There is probably no God. Now stop worrying and enjoy your life.'
Rev Jenny Ellis, Spirituality and Discipleship Officer, said, "We are grateful to Richard for his continued interest in God and for encouraging people to think about these issues. This campaign will be a good thing if it gets people to engage with the deepest questions of life."
The campaign is due to launch on buses in Westminster in January 2009 and have a four week run, although the BHA is considering keeping the posters up for longer after raising more funds for the campaign than anticipated.
Professor Dawkins was quoted by the BBC as saying, "Religion is accustomed to getting a free ride - automatic tax breaks, unearned respect and the right not to be offended, the right to brainwash children.
"Even on the buses, nobody thinks twice when they see a religious slogan plastered across the side.
"This campaign to put alternative slogans on London buses will make people think - and thinking is anathema to religion."
Responding to Dawkins' comment, Rev Ellis said, "As Christians, we respond to Jesus' call to love God with our minds as well as our hearts, souls and strength.
"Christianity is for people who aren't afraid to think about life and meaning.
"John Wesley, the founder of Methodism, believed that no one should be saved from the trouble of thinking because that is the path to understanding God."