CROYDON College has been heavily criticised by Ofsted for poor standards and failing to inspire its students.
Too many fail to get their intended qualifications and success rates for 16-18 year olds dropped in 2011/12, inspectors said in a report published this week.
The inspection, which took place in December, means the college has slipped from a "good" rating in 2009 to "requires improvement" – the second worst category.
Lead inspector Richard Beaumont noted encouraging features in teaching and leaders' "self-assessment" but said: "The quality of teaching, learning and assessment is not consistently good enough and does not sufficiently inspire and challenge all students to achieve their best."
He singled out art and design as "inadequate," health and social care as "good," and said all other subject areas needed to improve.
The college had been found to be inflating its results in 2009/10, sparking a turbulent period that inspectors and leaders acknowledged was "challenging".
Mr Beaumont said: "While the college has had some success in raising achievements, it is now in a much more secure position to raise standards."
The college's deputy chief executive, Andy Smith, described the report as "helpful", adding: "We are very pleased that they recognised our judgements are accurate.
"I think we also appreciate their commendation of the work that staff and managers have done to significantly improve the situation in a short space of time.
"They recognise that we do know where we are going, we know how to get there, and we are making progress."
Describing the problems in arts, media and publishing, Mr Beaumont said: "A significant minority of teaching and learning at advanced level is inadequate. In these lessons, the progress of students is often slow and teachers do not provide sufficient encouragement."
Mr Smith said systems were in place to improve teaching, and not just in those areas.
He said: "All staff are observed and all staff have an action plan which is not only about teaching and learning practice but also sharing the good practices that we have.
"In health and social care [rated good], we put in place an action plan early in 2010/11 and the new management has turned round that area and put in significant improvements.
"We would expect health and social care to be outstanding within the space of the next two years. Other areas are making progress and they too will get there."
The college was also criticised for its apprentice success rates, something Mr Smith said is being addressed.
He added: "Apprenticeships are time-limited so we do have students that are successful but they go beyond the time allowed.
"It takes some students longer to achieve their qualifications and it may also be that being in a particular place of work means they did not get the opportunities to demonstrate their competence."
Some courses also suffered from low attendance, the report said, a problem that Mr Smith sometimes stemmed from problems outside of college.
He said: "We are committing significant resources to supporting them in any way we can.
"We have a very good history of interagency cooperation."
