Every day the pupils in a Stevenage junior school look up at four words, high on the wall of their hall: “Reach for the Stars”. They are at odds with what used to be the unspoken motto of the town’s schools. “What can you expect of Stevenage children?” The head of Peartree Spring juniors, Penny Allsworth, explains: “That’s what they used to say.” She is the third person to tell me this today.

“We’re changing that: raising expectations and achievements, telling children they can do anything at all,” she says. “It’s a battle, but it can be won.”

I wasn’t expecting a battle here in leafy Hertfordshire, but that’s because I didn’t understand that its new-town status has left a legacy still felt in Stevenage classrooms 50 years after the first of the London overspill settlers arrived. There’s a clue in the sprawling estates, the neighbourhood shops, the measured green spaces, and the feeling that you could drive around lost forever if the areas of the town weren’t colour-coded and the street names themed - Verity is a short hop away from Grace. That clue is sameness.

“It’s very egalitarian, a one-class town,” says Susan Merton, an English teacher living in Sussex, but brought up here. “I grew up with no idea of the class system.”

“It was built as a workers’ town,” says Richard Westergreen-Thorne, head of Barnwell, one of eight secondaries here. “Old town apart, we’re only just beginning to get some four-bedroom houses.”

The trouble with homogeneity is that it’s dull. It’s hard to come here without that final line from Betjeman’s The Planster’s Vision creeping into your brain: “No Right! No wrong! All’s perfect, evermore.” And, of course, it isn’t. The pioneers, as those first settlers are now called, are these days the stuff of Year 10 oral history projects. A sociologist might point out just how closely linked the studied and the students are. Barnwell’s head certainly will.

“There has been a lack of aspiration. A feeling that Stevenage children didn’t expect much and that not much could be expected of them,” he says.

It was like that in the 1970s and 1980s when Ms Merton was a pupil at The Barclay School. The aspirational few, who had a taste of another life, aspired to get out. “In those days, Stevenage school-leavers split into two groups,” she says. “They either got an apprenticeship at British Aerospace, got married and stayed, or they left to go to university and never came back.”

Now pharmaceutical companies dominate the industrial zones. While schools have provided many service workers for them, homegrown PhD chemists have been rare.

Mr Westergreen-Thorne says teachers and the education authority are determined to change things. The place has a lot going for it. Two years ago it got a second bookshop. WH Smith was the first one.

Admittedly, the neighbourhood shops have largely closed, victims of the supermarkets. The 50 miles of town cycle paths are hardly used. But crime and unemployment are low. The planners kept traffic away from pedestrians and industry away from housing. And, although the trees appear all to be the same height, there are plenty of them, and lots of green spaces.

“We are on a mission to raise standards, to throw off the shackles of new-town status, in terms of being a working-class town with low aspirations,” says Mr Westergreen-Thorne, whose school is the site for a new community sports hall.

“We’re having some success, but it’s not a short-term project. I’m expecting this year’s GCSEs to be double last. No doubt I’ll be praised for an overnight miracle. But the work for those results started five years ago when I did my first teacher recruiting.

“Staff attitudes had to change. It’s a lot easier to be a caring school than to be a challenging school; much easier to say, ‘oh, all right then,’ to a child than to say, ‘Let’s get the job done properly.’ You can’t change that culture overnight.

“New estates are going up now with more expensive housing, which means people are beginning to aspire to more. You can see it at parents’ evening in the number of fathers who turn up and how many of them are wearing suits. You can see it in the numbers of children playing musical instruments.

“That doesn’t happen quickly. You raise your standards, word gets about, you become an oversubscribed school and the aspirations start to rub off on others.”

Apart from the Great Ashby development, which is well underway to the north, about 10,000 new homes are on the cards for green-belt land to the west of Stevenage. Just as the genteel old town gave way to the new and different so, in its turn, will the Stevenage of the 1950s and 1960s.

“The present town is rather like a large council estate in one of the big cities,” says Tanis Kent, a former primary teacher. She is now a county councillor and chair of governors for one of the Stevenage schools. “We have a lot of teenage pregnancies and a lot of single parents. At about 25 per cent, free school meals aren’t at inner-city levels, but there are very many low-income families,” she says. “And so many children have quite horrendous family circumstances and very unstable lives.

“Until recently, the teachers had low expectations because they were teaching Stevenage children. Parents didn’t feel involved. Then, a few years ago, the schools and the LEA made a bid to improve things. We started presenting pupil certificates for good work at the town council meetings. We began to be more like the schools in middle-class Hertfordshire, with classroom tests, homework and some uniform. We should start to see the results over the next few years.

“The literacy and numeracy strategies have worked on parents, because they have raised awareness and got them involved with their children’s education.”

Penny Allsworth walked into her 340-pupil school only weeks before an Ofsted report identified it as having serious weaknesses. In the two years since, the school has moved into a new building and out of serious weaknesses. The latest report is full of praise for its improvement.

Mrs Allsworth is tough and straight-talking. There are, she says, lots of lovely parents but there is quite a bit of “aggressive moaning”, too. Parental help is rare.

“Our motto is ‘Reach for the Stars’, and we spend a lot of time just talking the children up,” she says. “There are lots of single mothers in and out of various relationships, lots of seriously distressed boys whose dads have gone, lots of children on the streets in the evening. There are children who hardly have a civil word spoken to them at home and, of course, it shows in their language and behaviour.

“We have to raise their expectations and their self-esteem. We use lashings of praise: certificates, stickers and badges. We have to go really over the top with rewards to make them believe in themselves. We have to let them know what there is out there. We bring people in to talk about what they have done, jobs, the places they have seen. We’d like, if we can get the money, to do more school trips, to broaden horizons. Literacy and numeracy strategies have worked well here.

“There’s no doubt about it. There were low expectations among the staff. It was the old attitude of, ‘well, these are Stevenage children.’ This what you battle against. We had no parents at the annual governors’ meeting and only four at the Ofsted inspectors’ meeting. But we do have a parent-run cookery club and two or three parents have recently offered to help in school. We do all we can to make the place welcoming to them.”

Two wall displays - and there are many in this bright new school - catch my eye. There’s a gorgeous fabric sculpture of flowers in the hall. Elsewhere, there’s a lurid area devoted to newspaper cuttings on the evils of alcohol. Like the attitude of Stevenage heads, the two walls represent a mixture of realism and hope.

All the hope in the world, however, won’t work without staff, and Mrs Allsworth is having trouble filling two vacancies for September. It’s a common problem here.

“It’s not easy to attract teachers to Stevenage,” she says. “It’s more difficult to teach here than in some areas of the county and of course there is no London allowance. But we are on our way. With two more teachers we will succeed.”

Ambition and aspiration have at last shouldered their way into Stevenage staffrooms and classrooms. Leaving this oddly equal town you see the occasional business block rising above the low-level sprawl. It lifts the gaze and reminds you of the bigger universe. What do you expect from Stevenage children? If teachers have their way, in a few years perhaps the honest answer will be “Anything”.