A Christian sect which considers mobile telephones and computers to be the work of the devil has been praised by the Office for Standards in Education for providing good teaching.
The Exclusive Brethren has created an evangelical education empire of 43 private schools to teach children "away from damaging influences" in the state sector.
Schools run by the secretive sect, which models itself on strict Biblical teachings, are spread across the UK but are mainly in the south of England.
Pupils are banned from using modern technology.
A spokesman for the Focus Learning Trust, an educational group set up by the Brethren, said it hoped to register its 43 schools with Ofsted by the end of the academic year.
All private schools have to be registered with either Ofsted or the Independent Schools Council to show that they meet national criteria, although they do not have to follow the national curriculum.
Ofsted has officially accredited six of the sect's schools so far and been encouraged by their ethos and standards. It said the remainder were at "various stages in the process".
David Bell, the chief inspector of schools, said in his annual report last month that teaching in Focus Learning schools visited so far was generally good.
"Focus Learning provides good support to its schools and has developed a number of common policy documents that are of very good quality," he said.
But the conclusion has angered critics of faith schools. Keith Porteous Wood, executive director of the National Secular Society, said: "Denying children access to knowledge that would help them cope in the modern world is tantamount to abuse. It will leave them ill-equipped to cope if they later decide that life inside the Brethren is not for them.
"It is alarming that Ofsted, in its keenness to accommodate religion, appears to have suspended its critical faculties."
The Brethren was founded in 1863 and has 15,000 members in the UK. It believes the world is the domain of the devil and members spend most of their time in "safe places" such as meeting rooms and their own homes.
Socialising outside the sect is forbidden and members who leave are officially "shut up", ostracised for life by the rest of the Brethren "family".
The spokesman for the trust said Focus Learning schools observed the same rules as the Brethren, including a ban on computers, radios, television and mobile phones.
"We don't have such things in our homes, we don't have them in our businesses and we would not have them in our schools," he said.
"Children were educated extremely well - some would say better - before such things were dreamed up.
"I don't see any reason why that cannot continue to be the case.
"There is a general perception in the educational world that the teacher who needs to employ such gadgetry and gimmicks to get their message across is clearly not the most committed teacher."
Focus Learning schools educate around 1,400 children aged 11 to 17. They are independent and rely exclusively on fees or donations from the Brethren.
Pupils are members of the sect and more wealthy parents are encouraged to pay higher fees to compensate for those who are less well off. Prior to attending school, most children are educated at home. Pupils are offered a full range of GCSEs and vocational courses.
The trust said children are not banned from going on to higher education and a range of careers advisers, including officials from the fire service and National Health Service, visit the schools to discuss post-16 options.
But Doug Harris, director of the Reachout Trust charity, which provides support for ex-members of religious sects, said: "The basis of Exclusive Brethren belief is separation from the rest of the world, and that's exactly what is going to be passed on in their schools.
"People are only allowed limited access to the outside world and it can be distressing for them if they try to leave."