The headteacher at Devonshire Primary Academy, North Shore, is to leave at the end of term.
Nick Toyne told parents he wanted to “partially retire but also continue to work in education”.
He said: "The governors are already working to secure a replacement headteacher for the new year.
"When I leave I will do so in the knowledge that we now have the highest attainment in all areas for three years, the best teaching and highest standards we have ever had, the greatest resources, and the highest levels of good behaviour and attendance for a number of years.
"There is still much work to be done this term and we will continue as a school community to ensure that your child has the best possible educational chances available.
"Thank you for your continued support."