Two six-year-olds are taught to pass GCSEs. Now parents are asking: How, and at what cost?

A faceless building on a drab industrial estate in Hertfordshire is the unlikely setting for one of the most remarkable educational phenomena of recent years.

A faceless building on a drab industrial estate in Hertfordshire is the unlikely setting for one of the most remarkable educational phenomena of recent years.

Ryde College's two-storey headquarters, sandwiched between engineering firms and a printing concern in Watford, has become Britain's most famous producer of prodigies. On Thursday, Ryde produced record results for the sixth consecutive year, when Elissa Patel and Rajaei Sharma, both aged six, passed GCSEs in information technology.

Such extraordinary results have led to a high level investigation of the college's teaching methods followingaccusations that it was offering too much help to its child stars. The college was cleared of any impropriety by the OCR exam board but last night was still defending itself against allegations that it exploited its pupils.

This week's young successes are products of an unorthodox, part-time teaching method developed by a retired polytechnic lecturer who has shaken the educational establishment with a school he first set up in his front room.

The tutorial centre, set up by Dr Ronald Ryde 18 years ago, is thought to be the only place in Britain specialising in such early GCSE and A-level entries, and even offers courses for the under-twos.

Last night the college dismissed allegations by Neeta Radia that she came under intense pressure after her six-year-old son Krishan gained a place in The Guinness Book of Records two years ago. He became the youngest ever to pass a GCSE, with a C grade in computing, a record broken by a matter of days by the two six-year-olds' results this week.

Mrs Radia says she was urged to enter her younger son Suraj, then aged five, for the computing exam to satisfy the demands of the college's publicity machine. Mrs Radia said: "They would say to my son, 'Wouldn't it be nice to break your brother's record' and 'you are the next one'. I could not put my son through that." She said Suraj had started a GCSE project setting up a database, but had been given too much help with his coursework.

Last night the school said it had discouraged Mrs Radia from entering Suraj her younger son and refuted allegations it had exploited children and given Suraj inappropriate help. A college spokesman said: "At all times the well-being of the students is the college's primary concern and we would not carry out any activities that the parents and students were not in full agreement with.

"Contrary to what has been suggested, at no time did Suraj have any more help than that allowed by the governing exam board and had not, in fact, started any coursework towards his GCSE."

Earlier this week the college was cleared by an investigation at the OCR exam board into an anonymous allegation of cheating over coursework. A spokeswoman from OCR said an investigation had taken place "at a very senior level" and it had been decided that the correct grade had been awarded.

The dispute comes amid increasing pressure on parents and children to do well in exams, driven by the pressures of league tables and stringent entrance requirements for élite independent schools.

Peter Jennings, the director of the schools advisory service at Gabbitas Educational Consultants, said: "It is important to encourage children's strengths but there is a danger in becoming obsessive about it. Children need to grow up."

At Ryde College, computer teaching starts with "technology for babies and toddlers" courses, specially written for those aged between 18 months and three years.

Dr Ryde's youngest pupils learn about shapes, colours and simple vocabulary on their computers, which employ specially devised software. They are introduced to computer programming and basic word processing when as young as two and a half, and are taught to read and write on the keyboard in classrooms packed with state-of-the-art technology.

Teaching is carried out in small groups of five and even the youngest know the staff by their first names. Parents are encouraged to sit in with their children during lessons, which average about four a week. Ryde College recommends GCSEs for children from the age of eight, but offers them to younger children

Most of the college's 300 or so pupils come for two hours, twice weekly and their parents pay between £2,000 and £3,000 for a nine-month course. Entrance is by informal interview and the college insists it only turns away pupils with learning difficulties. Pupils are drawn almost evenly from state and independent schools, most from north London's affluent, professional Asian community.

Children are offered a specialised mix of basic "primer" courses from six upwards, in computing, maths, English and French. GCSEs and A-levels are taught in information technology and maths.

Lessons by the college's six staff are based on Dr Ryde's personal educational philosophy. He has condemned conventional schools for holding back young children who, he says, are keen to learn but constrained by the low expectations of the state system. He believes that the younger the child, the greater their capacity for learning. A 19-year-old is past his or her intellectual peak, and undergraduates are the "old -age pensioners of the academic world."

Dr Ryde set up the college in 1982, after retiring as the head of management science atNorth London Polytechnic. A graduate of the London School of Economics, who won a PhD in cybernetics from Brunel, Dr Ryde has for years been an advocate of accelerated education, claiming in the past that most children should be able to obtain all their GCSEs by the age of 12 or 13.

He opened the college, then called the Northwood Computer Tutorial Centre, from his home in Northwood, near Harrow, in north-west London. The college was born when he decided to coach his teenage sons and their friends through O-level. Within two years it had burgeoned into small classes at home when a neighbour asked him to teach her 10-year-old son. "When this boy's mother asked me to put him in for the O-level, my first reaction was that he was too young," he said in an interview last month.

"Eventually, she persuaded me to get in touch with the examination board, which said there were no age restrictions. The boy sat the exam and passed. Ever since then, I have believed that children should be allowed to develop according to their ability."

The college has now expanded to such an extent that it recently moved to its current home at Watford Business Park. It nevertheless remains a family concern. Dr Ryde's elder son Mike, a former IT consultant with a degree in electronics an communication engineering, is the managing director while the younger one, Jason, is also a director.

Pupils in fee-paying schools have taken GCSEs early for decades and David Blunkett, the Secretary of State for Education, is encouraging children in state schools to take some subjects as young as 11.

Early exams are already a feature of some high-scoringcomprehensives such as Thomas Telford School in Shropshire, which topped this week's GCSE league.

Jo Counsell, an education consultant at the National Association for Gifted Children, said that entries for early exams had to be assessed case by case. She said: "This college is very, very unusual. Certainly within our organisation there are lots of people who have taken their GCSEs early.

"Children who are very bright can be very demanding, wanting things that challenge them. My own feeling is there are parents who are incredibly pushy and wanting things very early for the cachet."