The Labour leader is expected to say that comprehensive schools are not working as well as they should be - because they do not do enough to take account of pupils' differing needs and talents.
He will underline the party's commitment to teaching children in sets for different subjects divided by ability, and declare that Labour is a "meritocratic" party which wants to bring out the best in individual children, in what will be seen as his strongest rebuff to the idea of mixed ability teaching.
His comments follow a controversial speech by David Blunkett, Labour's education spokesman, which was reported as an admission that comprehensive education had failed.
Mr Blair has also recently set out plans for "accelerated learning" which would see pupils moved up a whole year group for subjects in which they excel.
Mr Blair and Mr Blunkett are seeking to take a middle position between the Conservative Party's plans to increase selection and Labour's traditional attachment to uniform compre- hensive education.
Their task has been complicated by the decision in December by Harriet Harman, Labour's health spokeswoman, to send one of her sons to a selective grammar school in Kent.
Mr Blair is said to admire Mr Blunkett's focus on raising standards, which has clawed back some of the ground lost by the Harman affair.
The Labour leader's allies pointed toreports yesterday - which were vehemently denied - that Brian Mawhinney, the Tory party chairman, felt that Gillian Shephard, the Secretary of State for Education, had allowed Labour to set the education agenda.
Mr Blair will today describe John Major's plan to have a "grammar school in every town" as a waste of money which would benefit at most one child in 20.
"It is a dangerous distraction from the central issue of raising standards for all children," he will tell an audience at Didcot Girls' School.
But he will also mount a strong attack on the status quo in state schools, the vast majority of which still have a fully comprehensive intake.
"If one believes, as we do, in social justice, there can be no greater social injustice than giving a child a bad education," he will say.
And he will move to reassure the 150 remaining selective schools in England that, if parents want them, they will stay.
His speech is expected to form the basis of the section on education in the draft Labour manifesto which will go to the party's National Executive later this month.
A spokesman for Mr Blair said that he would be trying to sharpen the distinction between the Tories' desire to "return to the Eleven Plus" and Labour's aim to "modernise comprehensives".Reuse content