He told teachers and academics at London University's Institute of Education: "For some on the left, to talk of pressure on schools, teachers and pupils is to sell the pass. For me this typifies the reasons why the left has been losing general elections for the last 16 years instead of winning them.
"The people who suffer from lack of pressure are not the well-off and articulate. Instead, the losers are precisely the people who most need a hand-up in life because they were not born with natural advantages. It is traditional Labour voters who lose out when teaching is poor, discipline non-existent and the culture one which excuses low standards on ground of background or disadvantage."
While the old left emphasised support for schools without enough pressure on them to succeed, the new right thought the solution was pressure without support. Among the left, he said, it had become taboo to say bad teachers had to go. A Labour government would modernise the comprehensive system and encourage setting of pupils by ability in different subjects.
Streaming was a waste of talent but mixed-ability teaching was not an end in itself. "I am a pragmatist when it comes to high achievement." He pointed to a group of 11-year-olds in Birmingham who have just taken GCSE maths exams. "We must escape the obsession with rigid linkage of age and progress - whether at 11, 16 or 65."
In reply to questions, he said: "A lot of people will see setting of target groups as a breach of fundamental principle but it does recognise that there are children with different aptitudes within the comprehensive system." Mr Blair proposed a new grade of "expert teacher" to ensure exemplary teachers stayed in the classroom. "They do not want to go into management, yet they feel their achievement is not recognised."
Labour was also interested in a squad of "teacher professors", who would be given a term's sabbatical to tour the country, showing teachers how to teach.
He emphasised the importance of primary education and praised the assessment of five-year-olds being done by some councils such as Birmingham. There should be national guidelines for testing five-year-olds.
A Labour government would also change A-level and might abolish it. "My argument is not just that the A-level-dominated system does not work for the majority who do not do A-levels, but that the A-level curriculum is inadequate for those who actually do them."
In the long term, there could be a single school-leaving qualification at 18.Reuse content