A sixth-form college is celebrating an "extraordinary" turnaround after being hailed by inspectors who had repeatedly branded it inadequate.

Coulsdon College was this week rated 'good' by Ofsted, little more than a year after it received a second consecutive scathing assessment.

The Placehouse Lane college's transformation caught the eye of ministers, with the Parliamentary under-secretary for further education Matthew Hancock writing to applaud the achievement.

The change in fortunes comes after the college partnered with highly rated Reigate College in March last year, a month after being labelled inadequate by Ofsted for the second time in 15 months.

Inspectors who visited Coulsdon College in January 2013 criticised students' pass rates and a culture of low expectations among staff.

But Ofsted's latest report, published this week, said "Leaders and managers at all levels have been highly effective, in partnership with all college staff and students, in transforming the ethos of the college, raising aspirations and promoting high standards.

"Both the quality of lessons, and students' attitudes to learning, have improved and are now good."

Steve Oxlade, executive principal of the Reigate and Coulsdon College Federation, said: "No school or college has ever improved so much, so quickly and been awarded such high grades in a full inspection.

"Ofsted was incredibly thorough, observing almost every teacher, and has now officially not only declared the college out of special measures but concluded that quality is so good that they will be monitoring us from afar from now on, just as they do at Reigate."

Mr Hancock, minister for skills and enterprise, said in his letter to Mr Oxlade that he did not "underestimate the scale and magnitude of your achievement."

He added: "In less than a year to achieve an overall effectiveness grade of 'good' against the backdrop of two consecutive inadequate judgements is extraordinary."

The report, which follows an inspection in February, rated the college's teaching, learning and assessment and leadership and management as 'good'.

But it added student outcomes still required improvement.

Brett Freeman, Coulsdon College principal, said: "Ofsted has seen what we have achieved and recognised that this is something quite unique.

"I was especially pleased that teaching was praised so highly with many teachers graded outstanding by the inspectors. We’ve all worked so hard to achieve this."