Until this week, when her brother started university at the age of 12, Sufiah Yusof was Britain's youngest undergraduate. She is not an easy person to interview.
In a cold, bare kitchen, sitting at the family dining table, with her parents and sister Zuleika, four, she sits very quietly, hands in her lap, making no attempt to communicate.
There is no sign of teenage babble or boisterousness. Neither is there any noise from Zuleika, who is focused on drawing a circle with a compass, dividing it into fractions and carefully rubbing out mistakes with the dexterity of a ten-year-old.
Earlier this week, Sufiah, 14, began her second year at St Hilda's College, Oxford, reading maths. She won the place when she was 12, equalling the feat of child prodigy Ruth Lawrence, who began university life there at the age of 13.
Her brother lskander, who achieved an A in A-level maths when he was ten and a B in further maths a year later, and sister Aisha, 16, who gained top grades at maths when she was14, have just started at Warwick University-the youngest brother and sister to study together at university. Their elder brother Isaac, 17, is deciding between a career as a tennis player and a place at Warwick.
Their parents, Farooq, 40, from Pakistan and Halimahton, 41, from Malaysia, gave up their jobs to devote themselves to their offspring. They are selling their four-bedroom detached house in Northampton to be near their children at college, dividing their time between a rented house in Warwick and the home of Farooq's brother in Oxford. 'We are always present,' says Farooq.
Sufiah is by no means a young student going out in the world for the first time. She is a child who is fulfilling her parents' wishes. 'My first year at Oxford was quite fun,' she says meekly. 'I've joined the Maths, Islamic and Malaysian Societies.'
At 12, she was among the top eight junior tennis players in Britain, but now everything is subordinated to the pursuit of knowledge.
'In the second year at Oxford it is usual to do more sport and join more things,' she says, 'but I want to consolidate my work.'
She breaks off to answer the phone. It is lskander, who wants to know about a book on real numbers and topology.
According to Halimahton, Sufiah and lskander have terrible fights. 'The other night they were screaming at each other,' she says. This was not ordinary sibling rivalry, about which television channel to watch. These children fight about concepts.
'It was about logic,' says Sufiah, coming to life. 'You can't deduce a proof from the evidence he was presenting. We were screaming at each other.'
Most of the time she is silent - smiling while her father talks, endlessly. 'At Oxford, certain learned professors ask questions about children and learning,' he says. 'They seem confused. But to us, the answers are obvious.
'As long as children can sit down, listen and receive, they can be taught. It is not about sending them off to nurseries to learn. It is all done by the parents.
'It is about quiet, patient application and a whole currency of ideas and values which are provided within the home.'
The Yusofs educated their children at home after they looked at British schools and found them desperately wanting.
'There were difficulties about resources,' says Farooq, 'and problems about what the teachers can and cannot do. There were problems about knowledge, too - we believe that new ideas need to be examined at length. There has to be time for consideration and reflection, but there was no provision for this in schools.
'From their earliest years, we do everything to enable the children to learn. We are sensitive to them. We don't let them develop phobias about work.'
Hearing this, Zuleika, who had made no sound except for the scratching of her pencil, volunteers the word 'arachnophobia' and a discussion follows about spiders.
Farooq, who says his children are not gifted, believes he could teach almost any child to be as able as his own, even if they were handicapped or disturbed.
His methods hark back to a previous age. The house is kept cold and quiet, without any distractions. They rise at 7.30am and begin the day with Islamic prayers. He says these help to 'spark in the children the process of inquiry'.
After breakfast there are stretching and breathing exercises. An open window ensures there is plenty of fresh air, because Farooq believes it makes the brain sharper.
When they were educated at home, the elder children studied independent projects such as astronomy or Egyptology until lunch. In the afternoon, there was a walk and rigorous tennis training followed by more study, using rather battered grammar-school textbooks.
An important part of their education is also the 'exchange of ideas'. The children's facility is essentially right-brained, to do with maths and science, not the arts, but because they were literate and numerate by the age of two, they were able to interact in debate very early on.
'They are not passive,' says Farooq, 'they are taught to think. We invite them to put their point of view and always encourage them to be serious, not casual.
'Most people in Britain are sleep-walking,' he says. 'They haven't been taught to think. They don't exercise their critical faculties in any way.'
His methods have been proved right, in that the children excel at academic work. But Farooq and his wife are not just pushy parents.
The Yusofs are probably this country's brightest family, but they reject much of British culture.
Unlike British children, the Yusof offspring are not seen as individuals who can drift along and hopefully fulfil their potential; they are part of a highly organised group - the family - and they represent their father's ideals as a Sufi Moslem.
Followers of the Sufi branch of Islam are politically moderate, but still the Yusofs wanted to 'protect' their children from Western influences.
'We educated them at home because of the prominence of certain ideas in British schools,' he says. 'There is the idea that you can get on in life with no effort. We believe in application, hard work and traditional values.
'In Britain, goals and aims are presented by the pop culture that are dangerous, shallow illusions. Even children's television programmes are poor and propound the pop culture.
'On something such as Newsround they will suddenly advertise the Spice Girls, who represent the idea that you can get fame and money for no effort.
'Everything in this society is to do with immediate success rather than struggles, challenges and sacrifices.
'We felt that the children were growing up in an environment giving them the wrong messages. We have a material culture now, where the public is programmed for disposability, novelty and continual change. They even regard members of their families in this way. The element of sacrifice has gone, even towards their children.'
The Yusofs were very willing to makes sacrifices for their children. Farooq says that living between Oxford and Warwick is 'exhausting', and because he suffered polio as a boy in Pakistan, he has a bad leg, which doesn't help.
But willing sacrifice for the family is part of their basic beliefs. Everything is done for the good of the larger group. No part or individual is greater than the whole.
Farooq calls his children's successes 'a parallel learning project'. Except for the youngest, they all bear the academic workload of 18-year-olds. He calls this 'sharing intellectual challenges'.
When Sufiah finishes at Oxford, there are plans to send her to Harvard University in the U.S.. But she will have to wait a year for Iskander and Aisha to catch up.
Zuleika will also have to catch up. She is expected to sit her maths A-level by the age of six.
Farooq does not believe that many Western families could offer each other this level of commitment. Most people's lives are 'shoddy, shifting and unstable'.
'We are shielding our children from Western society,' he says, 'because we are so fearful of the alternative.
'We want their analytical skills to reach full development so that they cannot be exploited by this society.'
The children are fiercely guarded from the fripperies of fashion. 'We are bemused by constant changing fads,' he says.
In the living room there were no toys evident, only books, including a weighty Enid Blyton compendium, being read by Zuleika.
'They do have toys,' he says, 'but not mindless things such as Barbie dolls. Everything we do is for an end. They do not follow fashion for the sake of it.
'There is a sewing kit. Aisha made her little sister a doll. Then Zuleika tried to make one for herself, which was very meaningful. It showed a skill being transmitted to her. We want the children to pass on their creative skills to each other.
'We offer an environment which gives opportunities for self-fulfilment and protection from exploitation.'
This self-development is extended equally to boys and girls. The Sufi do not support the usual Islamic repression of women. But that does not mean the girls are as free as their Western contemporaries. For Sufiah and her sisters, there will be no exploratory relationships at college, even if they can escape the parental eye.
There was a slight hiccup last term when Sufiah was invited to a college reception for Princess Anne. Her personal tutor, Dr Irene Ault, warned her that there would be 'a lot of boozy young men there', so she didn't go.
Dr Ault unfortunately blotted her copy book shortly afterwards, by using an expletive during a lecture. Sufiah reported this to her parents with astonishment. It is not the sort of word ever to be heard around the Yusof dinner table.
Aisha cannot have a boyfriend,' says Farooq. 'That would not be considered as being to her optimal benefit.'
'We wouldn't accept the children having any kind of sexual relations. Of course, all the children know about sex, from a scientific point of view. And we realise that you cannot introduce ideas without experimentation, so we ask, what is going to be important to them - education or sex? Because of the way they have been brought up, the answer will be the former.
'They will not be exposed to U.S. television sitcoms or soaps, which stir up the emotions. They are taught that sex is something sacred, and that there is no value in having several different partners.
'In relationships you have to ask, how much would I sacrifice for this? The object of marriage is families getting together.'
'There is so much strength in the family,' says his wife, who laughs nervously. 'Asian people do well everywhere they go, no matter how poor they start out, because they believe in hard work, application and education. That will always win in the end.'
Sufiah and her sister were still quiet as mice. I wondered if she had any nerves about beginning a new term? 'I am looking forward to it,' she says calmly. 'There were no problems last year.'
'If you go to Oxford,' her father cuts in, 'it is your responsibility to discover the secrets of the universe while you are there. It is quite a holy place. I hope that people who are there do not treat it frivolously.'