Norwich's �21m Open Academy has suffered an early blow after inspectors gave it a notice to improve, the Evening News can reveal.

The judgment, which is one stop short of special measures, comes a week after the spectacular complex on the edge of the Heartsease estate was officially opened by the Archbishop of York.

It was the first of the Labour former government's landmark academies to open in Norwich and Norfolk, having replaced Heartsease High School in the old buildings in September 2008 and moved into the new building in September this year.

The academies programme, which has been criticised by opponents who feel it gives too much public money to one school, was established to drive up performance in areas of low achievement.

The official Ofsted report has not yet been published, but the Evening News has learnt of the notice to improve ruling - a fact confirmed by the academy's leaders.

Principal Jon Platten, who joined at Easter after leaving the role of headteacher at Alderman Peel High in Wells, admitted there was 'still work to do' at Open because inspectors wanted 'faster change'. But he stressed the 'many positives' in the inspection report.

He said: 'The inspection team commented favourably on improvements to the quality of teaching. Attendance has also risen so that it is now above the national average.'

Mr Platten said the inspectors recognised the fact that the choice of courses for older students was now more varied and appropriate. They also noted that the move to the new buildings had been successful.

He said pastoral care was described as effective and procedures for safeguarding students were described as good.

He added: 'We know that there is a job of improvement to do and feel that over the past 12 months, many good changes have occurred.

'Exam results have more than doubled in the last two years. The progress made by students puts the academy in the top 6pc when compared to similar schools nationally.

'The Open Academy already has an ambitious plan to build on the spectacular improvements of the last two years. The report will provide the school with the impetus to implement this sooner and quicker.

'We have an ambitious plan to transform teaching and learning and to support students in getting the very best results possible.'

Since becoming an academy in 2008, Open's results have improved strongly. The percentage of 16-year-olds getting five or more A*-C GCSEs including English and maths has risen from 16pc to 33pc this year. The percentage getting five good grades in any subjects has increased from 38pc to 57pc.

Open Academy is sponsored by the Bishop of Norwich, the Rt Rev Graham James, and Christian businessman Graham Dacre, who put �2m of his own money into the project.

Norwich's second academy, City Academy Norwich, opened in the buildings of Earlham High on Earlham Road in September 2009. Work to create the new �21.4m building will begin in January.

Ormiston Victory Academy Costessey opened in the former Costessey High buildings in September this year.