Schools need more freedom to sack poor teachers, research has suggested.
Almost three in four (73%) heads and senior teachers do not think they have enough freedom to dismiss weak members of staff, according to a study commissioned by the Sutton Trust.
This is a view shared by more than half (52%) of classroom teachers, with only a fifth (21%) of those questioned saying schools already have enough powers to weed out poor teachers.
Lee Elliot Major, research and policy director at the Sutton Trust, said: "The general reaction is that it takes a lot of time, and can be quite difficult, to address poor performance in teaching, whether that means getting rid of a teacher or trying to improve them."
Part of the problem is that if a weak teacher is sacked, they often stay in the system, for example as a supply teacher, he said.
"All of our studies suggest that the biggest factor in schools that affects a child's outcomes is the quality of the teacher," Mr Elliot Major said. "Teachers know that better than anyone, so if there are teachers that aren't up to scratch, there's a feeling amongst others that that needs to be addressed."
According to General Teaching Council for England (GTCE) figures, 15 teachers have been struck off for incompetence since 2001, and there have been 81 competence hearings in total in that time.
Last November, Ofsted chief inspector Christine Gilbert called for poor teachers to be removed from the classroom.
She warned that the quality of teaching in schools is too "variable", and too many schools tolerate "pockets of poor teaching".
The Sutton Trust study, conducted by the National Foundation for Educational Research (NFER), also found that half of the 2,170 school staff questioned (51%) are in favour of schools offering pay incentives of £10,000 above normal salaries to recruit and retain good teachers.