Black children are still getting a raw deal from the schools system, the Education Secretary Michael Gove said.
For far too long, he said, there had been "shocking, stubborn gaps" in attainment between children from black and ethnic minority backgrounds and their peers.
Mr Gove, who was speaking at City Hall - the headquarters of London Mayor Boris Johnson, told his audience: "Twenty years ago, Stephen Lawrence was brutally murdered on a London street by a gang of racist thugs - one of the darkest episodes in the history of race relations in this country.
"Twenty years on - we have to ask - have we created a truly colour-blind society in which every single child in this country, no matter what their background, no matter what their ethnicity, is give an equal opportunity to succeed?
"I don't believe we have - yet".
Figures showed black children had the lowest proportion reaching the required standard in reading, writing, maths and science at seven. They were also three percentage points behind the national average at the age of 11.
At 16, almost three-fifths of all pupils achieved five A* to C grade passes including maths and English - but only around half of black pupils did. Fewer also achieved two or more A-level passes.
However, the results of academies showed black and ethnic minority pupils outperforming their counterparts in local authority maintained schools. In addition, mixed race pupils showed a 5.7 percentage point improvement in GCSE results in academies compared to 1.3 percentage points elsewhere. "I do believe we are getting there - making progress," he added,