The headteacher of Eton college has said its plans to open three “Etons of the north” in deprived areas of England would not “cream off the bright kids” from local schools, amid concern from educators.

The world’s most famous private school is planning to open free elite selective sixth-form colleges in Oldham, Dudley and Middlesbrough by 2025 in partnership with Star Academies.

The announcement has been met with a mix of glee from local leaders and consternation from some headteachers. One said teachers were “upset and angry” while another questioned the need for more provision at time when colleges are being merged.

Simon Henderson, Eton’s headteacher, said the new sixth-forms – which would each admit 240 students annually – would “raise standards for everybody” and close the gap between pupils who do well at GCSEs but fail to achieve strong A-levels.

He said: “Some critics say ‘well, you’re just creaming off the bright kids – these kids were going to do well anyway’. The evidence suggests that’s not actually true.

“We hope that some of the partnership work we’ll be doing with the 11-to-16 schools in the area will benefit all of the students in those schools, not just the ones that end up coming to [Eton-Star’s] schools.”

Pupils at the new “Etons of the north” will be selected based on GCSE results and their background. Priority will be given to those eligible for free school meals, looked-after children, those from the most deprived postcodes and those who would be the first in their family to go to university.

Henderson said a rigorous admissions policy was being drawn up to prevent middle-class parents from “gaming” the system to monopolise places. The proposals will be put forward to the government’s free schools programme, a key part of its levelling up agenda.

In what may come as a relief to the teenagers of Oldham, Middlesbrough and Dudley, Henderson said it was “unlikely” they would wear the traditional Eton uniform of white tie and black tailcoat. However, he said there would be “certain features of an Eton experience that we definitely want to replicate”.

Students will be able to join debating clubs, learn Latin, be taught by Eton “beaks” in Oxbridge-style tutorials, attend summer school at the 582-year-old institution. The schools could also take on the Eton name, although that is yet to be decided.

Henderson said the three chosen areas all had a gap between students who perform well in GCSEs but fail to achieve strong A-level results. Each of the areas would need more sixth-form provision in the coming years, he said, and were chosen partly due to their good transport links.

Arooj Shah, the leader of Oldham council, hailed the initiative as a “gamechanger” for the borough and said it would benefit families “for generations to come”.

There has been concern, however, that the elite schools will only benefit a small number of already high-achieving pupils and would not improve attainment overall.

Tom Richmond, director of the thinktank EDSK and a former policy adviser at the Department for Education, said it was “astonishing” that the government’s levelling up plans “include a policy that, by definition, will only benefit a tiny number of pupils”.

He pointed to research showing that selective schools have no overall impact on attainment levels in particular areas, adding that Eton should have instead shared its resources to all schools in Oldham, Middlesbrough and Dudley rather than “locking away their supposed expertise in a very small number of schools to benefit only a very, very small number of pupils”.

Darren Hankey, the principal of Hartlepool College of Further Education, said he was concerned that the plans would have a “detrimental effect” on other schools and colleges in those areas who would lose students and staff.

He said ministers should instead better fund the existing providers, including school sixth-forms where per pupil funding has been slashed by 25% in real terms since 2010, adding that opening new institutions seemed to contradict government policy to shrink the higher education field.

Another school leader in one of the chosen areas, who did not want to be named, said teachers were “perplexed, upset and angry”. “If you said what’s top of my list for improving opportunities for children here, I would have got to 99 and still not mentioned a new sixth form.”