Bristol's longest-serving head teacher has announced he will step down at the end of the next school year.

Ray Priest, principal of the City Academy in Lawrence Hill, will finish next August after 18 years as a head teacher.

He hopes to support education in developing countries as well as supporting academies in the UK.

The 54-year-old said: "After 18 years as a head teacher I have decided that it's time to take on some new challenges. The academy is well placed to continue to improve under new leadership and I'm sure the new principal, whoever he or she may be, will build on our current story of success.

"The high point of my career has been seeing the students' amazed reaction to the new building and seeing more and more of our students going to university. And there are more great things to come, like the opening of our new vocational training centre later this year.

"I have been really lucky to have worked with thousands of amazing young people from this area and will really miss seeing them achieve in so many ways."

Enfield-born Dr Priest trained at St Paul's College, Cheltenham, and Bristol University, before starting his career in London.

In 1992, he was appointed head teacher of St George School, Bristol, and continued his headship up to 1999 when it became a community college.

In 2000, Tony Blair announced the academies programme – a government initiative to boost educational achievement in poor areas.

In 2003, a £30-million state-of-the-art school rose from the ashes of St George Community College. The City Academy was the first in the South West and results rose from 18 per cent of students getting five A*-C GCSEs to 60 per cent in 2008.

Every year the academy has been in the top five per cent of schools nationally for pupil progress.

In 2006, Dr Priest was awarded an honorary degree of Doctor of Education by the University of the West of England in recognition of his achievements. His successor should be appointed early next year.