Mixed-ability teaching and the fresh start in the first year of secondary conflict with the principle of 5-14 progression, Astrid Ritchie, spokeswoman for the Tories' education policy group, said.
Defending setting and testing in the first two years of secondary, two of the Scottish Office's most contentious policies, Mrs Ritchie said mixed-ability teaching was the one remaining problem area in the curriculum.
Methods failed to motivate able children, caused problems for those at the bottom and exposed teachers to stress.
"Attainment groups exist in primary schools and exist from S3, so why argue against it in S1S2?" Mrs Ritchie contended. As many as 35 per cent of lessons in S2 had been judged unsatisfactory during school inspections.
Bill Guthrie, vice-president of the Scottish Secondary Teachers' Association, insisted the secondary system was improving all the time without Government interference. "Some politicians would have you believe there is no testing going on in schools at all," Mr Guthrie protested. External testing in S1 was "at odds" with the 5-14 programme.
Mr Guthrie said: "The system seems to be working and it is down to the hard work of schools, teachers and pupils but politicians have taken the credit. "