Brighton and Hove’s controversial lottery-style school admissions scheme has failed to achieve one of its main aims, giving “have-nots” more access to better-performing schools, new research has found.

If anything, the system actually “slightly” increased socio-economic segregation, according to the study from London University’s Institute of Education and Bristol University.

Labour councillors from the authority attracted the ire of the right-wing press when they revealed that one of the reasons for introducing the scheme in March 2008 was to let “have-nots” compete for favoured schools against those who could afford to buy houses in the right area.

But their plan was not a pure lottery scheme and also involved new catchment areas. It is these areas that the study has found led to the scheme failing in its fairer-access goal.

“The introduction of a lottery on its own is not enough to equalise access to the high-performing popular schools,” the academics write. “The drawing of the catchment area boundaries is central to the outcome of the reform.”

But they do report a “significant change in the relationship between the poverty of a student’s neighbourhood and the academic quality of the school attended by that student”.

Some pupils from wealthier neighbourhoods were now attending less academically successful secondaries than they might have expected previously.

“These are the primary group losing out from the reform, balanced by a more diffuse group of winners who gained access to the higher-performing schools,” the paper says.

A Brighton and Hove Council spokesman said the system had been endorsed as fair by the chief schools adjudicator. The sample of pupils used for the research was too small to draw a firm conclusion, he said.