An academy backed by one of the UK's leading universities has been ordered to improve amid concerns about "unacceptably low" education standards.
The governors of Nottingham University Samworth Academy (NUSA) have received a "pre-warning" letter from Schools Minister Lord Nash saying the school must boost its performance or face further action.
The letter raises concerns that around 32% of pupils at the academy achieved at least five A*-C grades, including English and maths, in their GCSEs last year, down from 35% the year before and below the Government's minimum threshold of 40% of pupils reaching this standard.
It goes on to say that last year's GCSE results were "some way off" the school's own predictions of 44% getting at least five C grades, including the basics.
At the same time, pupils are not making enough progress, Lord Nash's letter said, and the school was judged to be "inadequate" by Ofsted following an inspection at the end of last year.
Academy co-sponsor Nottingham University, considered one of the UK's top higher education institutions, said that NUSA has been working in partnership with the Torch Academy Gateway Trust since October to improve standards following the summer's exam results
In his letter, Lord Nash concluded: "The standards of performance of pupils at Nottingham University Samworth Academy are unacceptably low."
He added that Education Secretary Michael Gove considers that standards are likely to remain so if he does not take action.
"Whilst I understand that there have been considerable changes to leadership and governance since November 2013, it is clear that plans are at a very early stage and significant issues will remain for the foreseeable future," Lord Nash wrote.
He ordered the academy's governors to respond to his letter within 15 days, setting out the action they plan to take to address concerns.
Nottingham University Samworth Academy, which is sponsored by Nottingham University and the Samworth Trust, opened in Bilborough, Nottingham, in 2009, replacing the William Sharp school.
It was rated as "good" by inspectors in July 2012, but this was downgraded following an inspection in November.
Inspectors found that pupils were making inadequate progress in many subjects because of poor teaching and that behaviour was inadequate, with a high exclusion rate, low attendance rate and poor punctuality.
They also warned that students' attitudes to learning were not good enough, and that the academy's leaders and governors had had no impact on improving teaching and learning.
Professor Alan Ford, pro-vice-chancellor for teaching and learning at Nottingham University, said: "NUSA was rated 'good' by Ofsted in July 2012. But as soon as it became clear that this year's GCSE results were not where they should be, we put a plan of action in place to improve teaching and learning, strengthen management and leadership, and improve results for pupils at NUSA.
"This represents a new phase for NUSA. It will mean a focus on improving learning outcomes for the school, strengthening leadership and providing the right environment for pupils to succeed. The partnership will use the Torch Academy Gateway Trust's track record of school improvement in conjunction with the outstanding teaching and training practice provided by The University of Nottingham's School of Education."
Jonathan Taylor, vice chief executive of the Torch Academy Gateway Trust said: "The main focus of our work at NUSA is to ensure that teaching is good or outstanding and students are able to achieve their full potential.
"We have introduced a comprehensive staff development programme and we are evaluating every aspect of work in the school.
"A key focus of our work this year is to ensure that Year 11 students are fully prepared for their GCSE exams in the summer. To that end we have introduced an extensive support and intervention programme available to all students.
"For the longer term we are putting in place systems and support for all year groups to ensure that student attainment is tracked and monitored. This will guarantee that every student has clear targets and understands what they need to do to succeed."
In total, around 40 academies have been sent pre-warning notice letters since September 2011.
The letters warn the schools to raise their game or face action - which could ultimately include being taken over by a different sponsor.
The Department for Education has previously said that it will not tolerate consistent under-performance in any type of school, which is why these letters had been sent.
The letters are the first warning to the schools that they must make substantial improvements, and those that fail to do so receive a warning notice.
Figures show that w arning notices have been sent to academies in three cases.