Top independent school heads have damned the state sector for producing teachers who have "formulaic" classroom methods and are uncomfortable teaching "off piste".
The state system produces teachers unduly focused on targets and Ofsted ratings who struggle to go beyond the syllabus to bring imagination and creativity to lessons, they have warned.
Young teachers or those coming into the private sector for the first time have to be "given permission" to embrace new freedoms because they are used to following strict rules, heads said this week.
The comments came with the publication of a report examining how the curriculum and assessment is affecting education in independent schools. The study, commissioned by the Headmasters' and Headmistresses' Conference (HMC), also expressed concern that state school teachers moving to the private sector were "less keen" on leading extra-curricular activities, particularly sport at the weekend.
Bernard Trafford, headmaster of Newcastle Royal Grammar School and a former chairman of the HMC, said while young teachers were generally highly proficient technically they had been conditioned into "delivering" assessment goals.
"This system has delivered on their set targets, but it's the kiss of death for imaginative teaching," he told The TES.
"When new teachers come here, they sometimes need the permission that it's OK to teach off-piste, that it's positively desirable. They are very good on things like classroom management, but they need to be told to loosen up."
Mr Trafford blamed the reluctance of teachers from the maintained sector to take after-school activities not on laziness, but a culture brought about by the pressures of the national curriculum.
Geoff Lucas, secretary of the HMC, said: "The post-national curriculum generation is very good technically at meeting the objectives that they are set and doing what's needed for assessment. It takes quite a lot of confidence to go beyond that."
Andy Falconer, chairman of the Independent Association of Prep Schools, said that the reluctance of teachers from the state sector to take extra- curricular activities, such as sport, was partly due to the "one- dimensional" aspect of training courses. He said: "Training colleges need to get across to their students how important that is."
James Noble-Rogers, executive director of the Universities Council for the Education of Teachers, said: "The very detailed teaching standards and closely prescribed content of teacher education programmes can raise the floor but also lower the ceiling. It can be a help, but also act as a straitjacket."
John Bangs, visiting professor at London University's Institute of Education, said the PGCE was "far too short" and did not allow enough time for reflection.
But he warned: "There is a nostalgia for a magic past, like in Dead Poet's Society or The History Boys, when teachers were free to go off-piste, but those sort of teachers were the exceptions to prove the rule and there was great inequality of teaching.
"We now have a system where standards for most are high across the board."
- Original headline: Top public schools claim state staff fail to inspire