A BURNLEY high school, previously rated as good, has been told it 'requires improvement' by Ofsted.
Standards in English at Sir John Thursby, was said to be 'well below the national average', according to inspectors.
However headteacher David Burton said they had highly positive feedback from inspectors, who acknowledged their good results last year.
The Ofsted report said the most able Year 11 students were not doing as well in English than similar students in other schools.
Lead inspector Derek Davies said: “Not enough teaching is consistently good and outstanding. The level of challenge in lessons is not always appropriate for some students and work is sometimes too easy.
“There are insufficient opportunities for students to think for themselves and extend their ideas in writing; consequently, the quality and quantity of work for too many students is not as good as it should be.”
Last year the school achieved a 10 per cent increase in GCSE results, the school’s best ever results and the biggest increase in the area.
Ofsted said last year's results were better than similar pupils nationally but that standards this year are set to decline.
The school was also praised for leadership at all levels and 'significant improvement' in mathematics.
It was also described as 'an inclusive school that serves its community well' with attendance and exclusion rates which are much better than those found nationally.
Headteacher David Burton said: "The school has improved hugely in the last few years. Leadership, management, behaviour and safety are all graded good and they agreed we are well on our way to being an outstanding school."