More than half the pupils in urban American schools lack basic literacy, according to a new study. It was released as President Bill Clinton attempted to make city schools a major focus of his political agenda for 1998.

The report has quantified for the first time the yawning achievement gap between urban and suburban schools. It could give Mr Clinton new ammunition for his proposed “education opportunity zones”.

“This country has paid attention to urban issues over the years with a lot of education and hand-wringing, but not come up with strategies at the federal level in Washington,” said Jenny Edwards, editor of the national magazine Education Week.

Eleven million children - a quarter of those in state schools - go to an urban school. (An urban school is defined as one where more than 75 per cent of children live in a city.) The report concluded that more than half of the fourth and eighth graders who took standard tests in these schools failed to reach minimum standards in reading, mathematics and science. In poorer districts that figure increased to two-thirds.

“Urban schools are fighting a battle they cannot win without strong support from local, state and federal political leaders, and from voters and taxpayers outside the cities,” said the report. “If the states, in particular, do not accept this challenge, the continuing national movement to improve schools will fail.”

As the US economy has improved in recent years, the state and local governments that provide the bulk of funding for school education have found themselves more flush with cash. That, combined with a growing frustration with urban schooling, has driven attempts at improvement.

In California, for example, Governor Pete Wilson has led a drive to cut class sizes across the board, a move likely to benefit the notoriously poor schools in places like Los Angeles. In big cities, such as New York and Philadelphia, there have been moves to break up factory-scale schools by putting 3,000 children into smaller institutions.

“We’ve got reason to believe that things are getting better. There are lots of signs of hope and success,” said Michael Casserly, director of the Council for the Great City Schools. Early improvements may not be reflected in the study, which took the most recent data from 1994 and 1996.

But while scores are improving in some areas he said that “the schools can’t make it all by themselves. America needs to take this stuff seriously and not walk out on all these kids, and close these resource gaps” .

The gap between inner-city and suburban schools is glaring. In New York state, for example, only 40 per cent of urban nine and 10-year-olds in the fourth grade reached the basic level in reading; in non-urban schools, the figure was 70 per cent. The picture was repeated for America’s big urban states on the East Coast, like New Jersey, Massachusetts, Pennsylvania, Connecticut and Maryland.

The reasons are familiar. While city residents tax themselves higher for education, lower incomes mean revenues may be less than outlying areas, but money is not the only problem. Quality teachers tend to avoid the sprawling and often unrewarding city school districts. Pockets of concentrated poverty and high unemployment are not conducive to learning.

President Clinton, whom critics accuse of running out of steam in his second and final term, has for weeks been hinting at a plan to target poor urban and rural school districts. There are suggestions that he is to make it the subject of a major initiative, possibly in his keynote State of the Union address, for the federal government to create “educational opportunity zones” modelled on a programme in Chicago. These would involve pledges of federal aid in return for schools bringing in reforms, such as adopting more challenging performance goals and getting stricter on promoting children through grades.