Heber Jentzsch, the President of Church of Scientology International, said that there was no legal obstacle to showing the advertisement on the ITV network, or to the run which starts today on the cable stations UK Gold and UK Living. The cable run was regarded as a "pilot" to test its impact, and it could be shown on mainstream television "in perhaps three months," he said.
It was also confirmed that the organisation, which is not regarded as a religion under English law, has applied for charitable status. A spokesman for the Charity Commission said, "The application is being considered."
Unveiling details of the commercial at a London press conference, Mr Jentzsch said its central theme was "trust" between and among people. "The message is that it is possible to be happy in this world," he said. "And we hope to be successful in spreading that."
The advertisement shows people from different cultures saying the word "trust" in different languages, and it ends: "On the day when we can fully trust each other there will be peace on earth."
Mr Jentzsch denied that the commercial was manipulative, and said those who described the church as a brain-washing cult were "anti-religious". "People can make up their own minds," he said.
In 1993, an attempt to show a similar commercial failed when the Independent Television Commission (ITC) ruled that the church was not a suitable organisation to advertise, a decision it reversed in April after legal and academic advice. Mr Jentzsch said this represented a "major step forward" for religious freedom in Britain, contrasting this country with the obstacles the church faces in Germany, where the film Mission: Impossible was recently boycotted because of its star Tom Cruise's connections with the church.
An ITC spokeswoman said the ITC would monitor the commercial to make sure it did not break any rules, for example by propagating religious dogma.
Scientology was founded in 1954 by the American science fiction writer L Ron Hubbard who claimed to have discovered Dianetics, supposedly the science of mental health.
It claims 100,000 UK members and 8 million world-wide but has been criticised for using "high pressure" tactics to gain new members, and has also been condemned for allegedly dividing families and charging substantial fees for courses.