Half of the pupils had attended Matthew Murray school in Beeston. The area of back-to-back houses is home to a large proportion of the city's Asian community; more notoriously, two of the July 7, 2005 bombers.
The other school, Merlyn Rees, was in Belle Isle, a 1940s social housing project, which has a largely white working class population and gave significant support to the British National Party in last year's local elections.
"We always knew it was going to be difficult," said Colin Bell, South Leeds high's headteacher.
The racial conflict was overt, said Alice Dunn, a Year 7 teacher. "Children will say, 'Yeah I know I'm a racist. What are you going to do about it?',"
She has been called a "Paki-lover" for helping Asian children. Yet she has also been struck by a feeling of injustice among some of the white children from Belle Isle who feel that they are not listened to as much as the Asian children.
The merger was part of the plans to cut surplus places by Education Leeds, the company which runs schools formed by the council and Capita. Merlyn Rees school had been put into special measures in 2003 and the building infrastructure at Matthew Murray was poor. Both had declining pupil populations. However, pupils and residents in each area strongly opposed the plan, which took place three years ago.
For the first year, teachers shuttled up the motorway between the two schools. Pupils then moved into the new buildings of South Leeds high last September.
The 1,380-pupil school stands at the end of a cul de sac in a housing estate just off the M62. In one direction, playing fields and woodlands signal the end of the city and in the other, far in the distance, is Leeds city centre. The shiny new building, created under the private finance initiative, is the more conspicuous for the poverty of housing surrounding it.
Trouble flared almost immediately. Fights and incidents continued roughly every month, ranging from scuffles to what the pupils described as "riots".
The scale of the problem demanded radical thinking. So South Leeds high came up with an innovative scheme to bring its pupils together, focusing on the 210 students in their first year of secondary education.
The Year 7 pupils work predominantly in classes which stay in one group, much like at primary school. They focus on cross-curricular project work rather than separate subjects. Each class is deliberately designed to have pupils from a mix of backgrounds and encourages them to work and play together.
The Year 7 project has been managed by Michael Hill, the deputy head, and is based on the Opening Minds programme created by the Royal Society for the encouragement of Arts, Manufactures and Commerce, better known as the RSA. Mr Hill said the scheme helped pupils become more creative, independent and emotionally literate learners. "We didn't throw out the national curriculum," he said. "It just wasn't the starting point."
Eight teachers were invited to take part in the project, two from each subject specialism, and they wrote a new curriculum. John Swales, the RE teacher who led the team, said: "We encourage teachers to take risks. If there is a better way of educating them than in the classroom and getting the text book out, then go for it."
The struggle has been uphill, in all senses. The school was built 200 under capacity, based on projected figures, so portable classrooms have been built at the top of a small hill to accommodate the overflow. These have provided the Year 7s with a home.
Some staff conceded they have been "a trial" in bad weather, but Mr Swales said that working up on the hill has helped create "a community within the school".
The problem is that when the school bell goes, they return to an environment that can "outspokenly racist".
"We've got them for five hours a day and when they go home they're getting completely different messages," Ms Dunn said. "Things will only change if we make a difference to these kids and when they're adults they pass on the right messages.It might take a very long time. A generation."