Pictures of smartly dressed children beam from the walls. Colourful charts record perfect attendance and behaviour. Evidence of prowess in woodwork, art and cooking is spread around the classrooms. Pupils are getting the sort of one-to-one attention most parents can only dream of - except most would never want their son or daughter to end up here.
This is Aldine House, one of 19 secure children's centres in England and Wales. They are home to some of the country's most notorious young criminals, children who have been responsible for acts of violence, arson and even murder.
It is to centres such as Aldine House that Jon Venables and Robert Thompson, the killers of James Bulger, were sent after their conviction. They also house the two brothers who savagely beat and tortured two boys in South Yorkshire last year.
At the end of a leafy lane, nestled on the edge of the Peak District near Sheffield, Aldine appears more Big Brother house than Victorian prison. Modern, bright and spacious, the brick building is surrounded by cameras and fences. All doors are kept locked. Visitors are screened and enter through airlock-style doors. Walking through the centre requires every door to be unlocked and then locked behind you.
At Aldine, the staff's job is not only to rehabilitate some of Britain's most disturbed young people, but also to act as parents, friends and teachers. But if the idea of trying to teach children who have committed sometimes horrendous crimes is daunting, those who work here seem unfazed.
Dave Newman was a youth worker and then a teacher at challenging schools before he arrived here, so he is used to dealing with problem pupils. "We have the same ethos here as in any other school - we want the children to do well," he says.
Judi Booth taught in mainstream schools in Leeds, but was frustrated by the lack of time she was able to dedicate to pupils' welfare. She says she is much happier working in a secure unit.
"We try to have a close relationship with the children," she says. "I feel like I'm making a difference here in a way I never did before."
There are places for eight children at Aldine, which currently houses five boys and three girls. The centre's head of education, Liz O'Connell, who is also a qualified teacher, tries to provide everything that these children would find in a mainstream school. But while there are the same brightly coloured wall displays as in thousands of schools, this is by no means a typical classroom environment. Alongside their criminal past, many of the children at Aldine fit a pattern: a poor record of school attendance, low levels of basic skills and an unfavourable opinion of the value of education.
"It's not easy for them. They have to cope with new things, like group work, for the first time," says Mr Newman at the end of a particularly challenging maths lesson on calculating angles. "The intensity is a bit much for some at first."
His class may have been small - just two pupils - but is typical of lessons at Aldine. It comprises a 12-year-old and a child approaching GCSEs. The difficulties in teaching these children can be off-putting for many teachers, says David White, a member of the centre's governing body.
"What is expected of teachers here is a massive challenge. It is an intense environment where the children are together all the time, and so much is expected of them," he says.
"They have to cope with classes of extreme mixed ability and age and teach a range of subjects, as well as having to keep on top of behaviour. Mainstream teachers could learn a lot from our staff here."
The eight children at Aldine have two full-time teachers, two teaching assistants and one higher-level teaching assistant. They are mostly taught in groups of four.
It is perhaps not surprising that Kerry Hague, Aldine's manager, finds it hard to recruit teaching staff. Those who currently work at the unit have previously taught in mainstream schools but moved into teaching young offenders because they felt they could make a difference to their lives.
The teachers get special training to help them to cope with the particular demands of life inside a secure unit, and to develop expertise in bringing calm to potentially difficult situations. Good humour and patience mean that, while lessons are often lively, they rarely descend into disorder, despite the backgrounds of the pupils.
Staff must be alert to early signs of frustration. Children who need to calm down are taken elsewhere by a teaching assistant before they cause problems in class. In one case, Mrs O'Connell's sex education lesson had more potential than most to lapse into chaos, but a discussion about herpes and genital warts is successfully kept on track, despite the use of some gruesome pictures.
While the surroundings might be unusual, the basic structure of the school day would have a familiar ring to many teachers. The week starts with an assembly in which children are encouraged to share their achievements with staff and pupils. They then embark on a timetable which would not look out of place at thousands of other schools - maths, English, technology, PSHE and science.
There is regular feedback: sticker charts adorn corridors and all pupils get reports. Lunch is eaten in the canteen with teachers, and to avoid any trouble children go one by one to choose their food from the wide range of options available. Staff chat with them easily, on this occasion mostly about football.
Pupils celebrate the same events as their friends on the "outside". They recently organised a "cook-athon" for Sport Relief and put on a buffet and a show to raise money for a local hospice.
The difference between the "home" and "school" parts of the day are emphasised. Within "school", pupils have voted to wear a uniform and have even designed their own school logo. And beyond lesson time, their rooms may be locked once they are inside, but they are still a private space. For some, it is the first time they have not had to share a room with others.
Aldine House was purpose-built. As well as the classrooms and canteen, pupils also have their own kitchen for home economics lessons and a spacious room that can be used for group meetings or to relax.
But while everyone at Aldine works hard to create a sense of normality, there is no escaping the fact that this is a secure environment. Provision of internet access is a case in point. Engineers had to be called in to get a wireless signal through the metal walls. And while the children are allowed to use the web, they have no access to email or social networking sites.
Bizarre as it sounds, for some children Aldine is their first stable environment. "For most, it is the only time they have been allowed to be children," says Mr White. "It is the first time they have had three meals a day or had their food cooked for them. That is a lot to get used to - and as well as that, they have to concentrate on improving their behaviour."
Some find it hard to adapt to this change, particularly when, on arrival at the centre, they also undergo therapy to encourage them to take responsibility for the actions that led to their incarceration. Much of the counselling aims to get children to understand what causes their anger or loss of control.
"It is a big task getting them to understand why they did those things, and why they need to change," says Nick Barber, the centre's assistant manager. "Our aim is complete behavioural and attitudinal change."
This includes getting the children to learn how to use their leisure time productively. As well as 30 hours a week of lessons, they also have 12 hours of guided "enrichment" activities such as sport and drama. Therapy also aims to equip the children with the skills to deal with difficult situations. "We usually see a very quick change," says Mr Barber.
Aldine staff have become specialists in helping children who have been bereaved or suffered loss, such as a parental divorce. For that reason, some of the most fragile young offenders are sent here.
Secure units are just one of the possible destinations for young offenders given custodial sentences. Young offender institutions or secure training centres are also available, but these prison-style environments have higher reoffending rates and lower levels of educational achievement.
The high ratio of staff to children and the emphasis on education have contributed to the reputation of secure children's centres as the most effective part of the young offender estates. Children can learn, gain qualifications, undergo therapy and make plans for their future life.
The intensive treatment on offer means the centres tend to be favoured by courts as a destination for vulnerable children - those at risk of self- harming, or who have been bullied, abused or neglected, those addicted to drugs or alcohol or children who would find it hard to cope in a unit that was more like a conventional prison.
But most young offenders do end up in such environments. The Youth Justice Board (YJB) funds just 143 places in secure children's homes. About 2,100 under-18s are imprisoned in the UK, the majority in young offender institutions. The reason for this bias seems clear: it costs about pound;210,000 a year to keep a child in a secure unit, compared with pound;34,000 in a young offender institution.
Perhaps as a result, the number of secure children's centres has fallen over the past few years. In 2004, there were 27 in England and Wales; now there are 19. The YJB says the need for such centres has declined. Secure children's centres are considered particularly suitable for the "younger" of the young offenders, but in 2007-08 only 190 children aged 12-14 were sent to these centres, falling to 168 in 2008-09. The units are often run at only 80 per cent occupancy.
Critics claim that by reducing the number of places it funds and forcing the closure of some centres, the YJB is aiming to work with a smaller number of local authorities and make it easier to drive down costs. The board gives only short-term contracts to the centres and says this encourages competition. But the emphasis on cost ignores the varied effectiveness of the different parts of the youth custody estate, says Roy Walker, former chairman of the Secure Accommodation Network.
If we are going to lock children up, secure children's homes offer the best investment. They have better levels of staff and opportunities and offer a better chance of children being returned to their communities successfully. Surely offering all those weeks of education a year with the emphasis on literacy and numeracy is good value," he says.
Frances Crook, director of the Howard League for Penal Reform, agrees. "Secure children's homes provide the most effective care and are usually closer to the communities children come from," she says.
At Aldine House, teachers are proud of their pupils' achievements. Every child who stays there leaves with an externally accredited qualification of some kind, ranging from GCSEs to short "key skills" courses. One girl completed five GCSEs in just nine months. Another now plays for a Premier League women's football team.
"If these children were in mainstream school, they wouldn't get qualifications until they are 16; here they start at 10," says Mrs O'Connell. "We encourage success. The academic ability is there. Our job is to harness that learning."
Many children spend less than six months at Aldine, and some are there for just a few weeks. Some youngsters arrive at the unit on remand and are waiting for their case to come to trial. These children must take all their possessions to every court hearing, not knowing where they will be sent.
The sometimes rapid turnover at the centre means traditional school holidays would be too disruptive, so breaks from schooling are shorter and more evenly spaced. In this case, new modular qualifications are a godsend for staff.
But despite the short stay involved for many of their charges, staff develop a strong bond with the children and fight through the youth justice system to keep for as long as possible those who reach an age where they are meant to be moved to another type of young offenders' institution or an adult prison.
"We always put a strong case to keep children here," says Mrs Hague. "We always have evidence to show they are doing well. But ultimately, decisions are made purely for `body count' reasons and it is not always a two-way process."
Staff are forbidden from communicating with the children once they have left the centre, sometimes with horrendous consequences. Mrs Hague recalls one girl who was at Aldine House for two years. She had made good progress and was intending to take A-levels, but when she was too old to stay at Aldine House, she had to move into a young offenders' institution, where she began to self-harm.
"If we had been able to talk to the staff there and work with them, we could have told them it was something she did when she came here, and we could have helped her," she says.
Towards the end of their stay at Aldine, children's behaviour tends to change as they become anxious about life on the outside. And there is much to be apprehensive about. Many schools are reluctant to take these youngsters on, although good links between Aldine House staff and Sheffield City Council mean that this situation is changing, although the offenders are not necessarily from the surrounding area.
When the time comes for them to leave, the children are given a present of kitchen equipment, including items they are unlikely to have at home, such as oven gloves and potato peelers. If they are close to finishing their courses of study at the time of their release, they may even return to sit their exams.
Inevitably, some of the children will end up reoffending and will return to a secure institution. Others will continue in education and try to create a new life and leave their previous offending behaviour far behind them. Their future is uncertain, but for many, the stay at Aldine House will have given them stability for the first time in their lives.