Katie Holmes' decision to file for divorce from Tom Cruise, reportedly over concerns about the role of Scientology in the life of daughter Suri, has turned attention to the schools that prepare children for a life in the controversial religious group, including one boarding school in England that has reportedly funneled dozens of students into Scientology's most secretive and hard-core unit.

Greenfields School in England's Sussex countryside describes itself as an "independent day and boarding school from 2 to 18 years old." But those with a close knowledge of the institution tell London's Evening Standard it is "the school of choice" for employees of Saint Hill Manor, Scientology's UK headquarters.

Former students at Greenfields told the Standard that each year, as many as 10 students "disappear," from their normal educational track and are rumored to have been sent to the United States to enroll at Sea Organization, the religious order of the Church of Scientology. Sea Org, which boasts about 6,000 members, is housed in a compound near Los Angeles and devotees purportedly wear Naval-style uniforms.

Twenty minutes into my visit to Saint Hill Manor last week, a Georgian house on the edge of East Grinstead and about an hour on the train from Victoria, a uniformed man with a dog approached me, and he wanted to check a few things.

“You are a Scientologist?” he asked, with a Polish intonation.

“No, I’m just having a look around.”

“So you are a guest,” he said. “We like to know who is here.”

The staff at Scientology’s UK headquarters are alert to the danger posed by outsiders, their movement the subject of criticism from former members (“defectors”), children’s campaigners and courts around the world since its birth in the 1950s. Scientology’s beliefs about a dictator alien called Xenu who blew up his people 75 million years ago by exploding volcanos with H-bombs have attracted ridicule since they were published against the church’s will, and advocates have long denied accusations that their movement is a cult or a front for a money-making operation.

The announcement this week that Katie Holmes and Tom Cruise had agreed divorce terms rounded off another period of intense scrutiny of the church. Speculation that Holmes was motivated by concerns about her daughter, Suri, being educated by Scientologists and initiated into a secretive group called Sea Org were given credence by the couple’s joint statement, in which they sought to “express our respect for each other’s commitment to each of our respective beliefs”. An insider told celebrity news site Radar: “Suri isn’t permitted to be exposed to anything Scientology-related and this includes going to any Scientology churches, parties, etc. Katie made sure this was ironclad.”