It could take a decade for the government's reforms to improve standards in England's secondary schools, David Blunkett has argued.
The former education secretary said changes to nursery and primary schools had raised the results of national tests in the late 1990s.
During an interview with his successor, Estelle Morris, on the Teachers' TV channel, Mr Blunkett said it would be ten years before improvements in secondary schools would take effect.
"In 1997 we adopted the phrase 'standards not structures'", he noted.
"The first policy document of the Blair government was the white paper on education, including Sure Start, literacy and numeracy.
"I believe that we did start to change the world but that it will take another decade to achieve at secondary what we achieved at primary."
Mr Blunkett acknowledged his drive to introduce citizenship lessons, which became a compulsory part of the national curriculum in 2002, had failed, but insisted he believed it was crucial to have citizenship on the menu to prepare youngsters for modern life.
"I don't think we have entirely got it right yet. We need to renew our commitment to ensure citizenship is not seen as a diversion or a burden," Mr Blunkett said.
A spokesman for the Department for Education and Skills said: "Thousands of secondary school pupils have already benefited from the reforms and investment that this government has made in education - Key Stage, GCSE and A-level results, international comparisons, and Ofsted reports - make this clear.
"Year on year standards are rising - 64 per cent of students now leave school with the five good GCSEs they need and we are already taking forward the reforms that will ensure this is the case for all."