The Government's drive to raise standards in schools could leave disadvantaged children slipping even further behind their classmates, according to research published today.

The direct challenge to Labour's core education policy comes from London University's Institute of Education, where the government standards adviser, Michael Barber, was professor of new initiatives until taking up his current post earlier this year.

The study, "Can school improvement overcome the effects of disadvantage?", argues that a government strategy of "blame and shame" will merely lead to cynicism among teachers of poorer pupils. Only last month, the schools standards minister, Stephen Byers, insisted poverty would be no excuse for under-performance by schools, which must set targets showing how they intend to work towards national standards goals.

The Institute of Education director Professor Peter Mortimore and co- author Geoff Whitty, claim in their report that "blaming schools for the problems of society is unfair and unproductive".

Initiatives by successive governments have failed to break the pattern of persistent underachievement among children from deprived homes, says the study, through a lack of adequate targeting, resources and co-ordination with other services.

Initiatives such as free school meals and uniform grants have done too little to compensate for the disadvantages experienced by poorer children, who are more likely to be physically weaker, have less energy for learning and less opportunity for study at home than their better-off peers.

If the gap between rich and poor is not to widen further, according to the study, there must be a clearer recognition of what schools can and cannot be expected to do, with more co-ordination with other agencies, more support for disadvantaged pupils and greater recognition for teachers who work with such children.

"Policies which tackle poverty and related aspects of disadvantage at their roots are likely to be more successful than purely educational interventions in influencing overall patterns of educational inequality," the report concludes.

The Government justifies its "no excuses" stance by pointing to differing levels of achievement by schools in similar areas as evidence of the potential for some relatively poor performers to raise standards.

Policies aimed directly at helping poorer pupils include the setting up of education action zones in inner cities and - as revealed last week in The Independent - rural areas in order to target resources and support to those in most need.