Hinchingbrooke School’s headteacher Andrew Goulding has denied claims there is cause for concern about the number of teachers who have left the academy.
Mr Goulding was responding to the union NASUWT, which said it was worried that so many staff had left the school during this academic year.
Five teachers left the Huntingdon school at Christmas while another member of staff left in February.
The school is advertising seven posts, including the head of sixth form and a leader of the modern foreign languages.
Mr Goulding, who took over in September 2012, said: “The turnover of staff has been 13 per cent, 16 per cent and 11 per cent in the last three years.
“There is not a significant difference that would show any cause for concern.
“There are a number of staff leaving for retirement, promotion and for personal reasons.
“In schools there are promotions available but sometimes staff have to move to other establishments for promotion.
“It’s the sign of a healthy organisation that develops its staff, enabling them to get promoted.
“I know that sometimes students and parents can get upset when a loved teacher leaves after spending a number of years at the school, but I am excited by the quality of the teachers who will be starting in September.”
Geoff Fewtrell, Cambridgeshire representative of NASUWT, claimed morale was pretty low among teachers in Cambridgeshire and that Hinchingbrooke was no exception.
“If you lose 12 staff at Christmas, it’s quite difficult to get the right people in to replace them at that time, it could affect the quality of teaching,” Mr Fewtrell said. “It could be due to the change in philosophy following the change of headteacher.
“It’s quite worrying to see the number of teachers leave, especially with its recent Ofsted report.
“We were all quite surprised Hinchingbrooke has gone from excellent to needs improvement.
“That’s quite a drop, especially as Hinchingbrooke has extra resources with its charitable status.”