Police officer Ilyana Martinez, sitting in her squad car outside the gates of Feaster Edison elementary, describes how the school was once her toughest beat.

“The first year that I was here,” she says, “I had to bring another officer with me into the classroom, just so I could teach.”

She ran off a list of problems: vandalism, assaults on teachers, “drug babies”, transient families, parents “who basically had a lot of contacts with police”. But now, she said, “it’s a different school. . .They promote this school pride, and the kids are just sucking it up.”

The city of Chula Vista lies on low coastal land between San Diego and the Mexican border, just a few miles to the south. Feaster Edison was until last year at the very bottom of some 30 district schools, said principal Catherine Rodriguez, and had become, she said bluntly, a dumping ground for teachers.

The school has a heavy proportion of native Spanish-speaking pupils; three-quarters of the pupils are Hispanic. Rodriguez was among the teachers assaulted in the neighbourhood. “It definitely was a very ugly place,” she said. “It’s not now.”

Last year, the 1,000-pupil school was taken over and renamed by The Edison Project, a private company that runs 25 state schools in the US and is now hoping to set up shop in Britain.

Last week it emerged that the firm has drafted plans for a Government-sponsored education action zone based on Stamford high, a 600-pupil comprehensive in Ashton-under-Lyne run by Tameside council, Manchester.

Edison’s mantra is that even at the bottom of the school scale, in California, a state that has one of the meanest education spending records in the US, it can revitalise schooling, and make a profit at the same time.

At Feaster, Edison has brought new computers, staff, classrooms, shiny educational ideas, a fresh coat of paint and a school song, and undoubtedly a new sense of hope. It restored music, language and PE programmes that have been cut in many California schools.

“If you walk around, you’ll feel the atmosphere,” said Maureen Rees, a newly-hired “senior teacher”.

But the mystery here and with other Edison schools, is how long this first flush of optimism - and spending - will last. The company aims eventually to make a profit of 3 to 4 per cent on school management contracts, insisting it can save public money and save schools at the same time. Bright ideas aside, its bottom line is profits, not philanthropy.

Edison to date has been financed by private investors whose injection of $160 million (pound;96m) in start-up cash has allowed it to spend $1m to $2m in every school it takes over. “Sooner or later, they have got to get the money back. So where is it going to come from?” asks Alex Molnar, a professor of education at the University of Wisconsin at Milwaukee. “It just doesn’t make any sense.” If the Labour Government buys into Edison, he says, they will be encouraging the “spread of a bad idea”.

The Edison Project has come to Feaster with its trademark combination of new curriculums developed at top teaching universities and trumpeted in glossy corporate brochures. The day, for pupils from kindergarten through sixth grade, (roughly ages 6 to 12), begins with 90 minutes of reading in a programme called Success For All.

Every teacher is guaranteed an hour-and-a-half of “personal development time” every day, and gets a laptop connected to a school network. These allow instant tracking of late and absent pupils; absentee rates have already fallen.

Edison’s stated aim is to put a computer in every child’s home; as part of the deal, they offer training courses to families, in an effort to increase parental involvement.

One of Edison’s trade marks is adding an hour a day and six extra weeks to the school year, along with all-day kindergarten - unusual in state schools. Over a child’s school career, this adds the equivalent of several extra years of education.

It has not, apparently, endeared the company to Feaster pupils, who volunteer a list of complaints about everything from the food, to the playground.

“The only thing it means is a shorter vacation, and I don’t think it’s enough,” says one 12-year-old. “There’s no recess, there’s not very much time,” said another. “I used to like this school a lot, but not now.”

Along with the computers, Edison has paid for 14 new temporary classrooms - “relocatables” - at a cost of $60,000 each.

As a charter school with semi-independent status, the school now receives about $4,200 per pupil from the state, or about $4m a year.

This year the “net net” profit at Feaster was just $20,000 - effectively nothing - said business services manager Reggie Depass, formerly a sales manager with a big canned tuna firm.

Cost savings, he suggests, will come from constant scrutiny of school spending, closely managing the purchase and use of everything from copy-paper to air conditioning.

“The minute you become accountable for something, you are not going to be wasteful,” he argues.