The findings were announced after a recent two-day monitoring visit of Unity College, a Church of England secondary school in Trinity Avenue.

Unity College was placed into special measures – the lowest ranking possible by the Government's education watchdog – following an inspection in February 2008, for failing to give its students an acceptable standard in education.

The latest report said: "The quality of teaching and learning remains very variable and is inadequate.

"The college has introduced a wide range of measures designed to improve the teaching, including the use of more rigorous criteria for judging lessons, targeted training and support for weaker teachers and the use of 'toolkits' to help teach engaging lessons.

"However, these actions have yet to have a discernible impact in raising the proportion of good and outstanding teaching and the college recognises this."

Inspectors said a crucial weakness in less successful lessons involved the secondary school not meeting the needs of students speaking English as an additional language and those with learning difficulties or disabilities, other than pupils with statements. Teachers' expectations of students were also said to be too low.

However, good or outstanding teaching was reflected by students engaging in activities and teachers' feedback to pupils on their progress.

Since the last inspection, the school has changed its timetable so lessons are shorter which has improved student interest and involvement.

In 2007, GCSE results climbed from 30 per cent gaining at least five grades A* to C to 38 per cent this summer.

The report added: "However, the college failed to meet its 2008 target of at least 45 per cent gaining five grades A* to C.

"The proportion achieving at least five grades A* to C including English and mathematics is 22 per cent, well below the target set by national government."

Inspectors said students' personal development and well-being remained satisfactory with pupils benefiting from opportunities to undertake extra responsibilities.

The report said principal, Margaret Gwynne, gave strong leadership and a number of initiatives had been introduced to address under-performance and low level disruption but it was too early to judge its impact.

A spokesman from the Peterborough Diocese's board of education said: "This is a progress report not a final assessment and we are pleased to see it recognises that some improvements have been made.

"The report also recognises there has been insufficient time to implement all the necessary requirements and the school is continuing to address them."