In 2005, 9 per cent of pupils at Malory school in south London achieved five or more good GCSEs.
A year later, it became the Knights Academy, part of the Haberdashers'
Aske's Federation, and the figure rose to 29 per cent.
Sir Cyril Taylor, chairman of the Specialist Schools and Academies Trust, said the federation was an "outstanding case study of collaboration" under the leadership of Dr Elizabeth Sidwell.
Formed in September 2005, it consists of two sister facilities - Hatcham College and Knight's Academy. Dr Sidwell, former head of Hatcham, became chief executive of both schools.
"When I visited the school last July, I was frankly stunned that so many characteristics of a good school had been achieved in such a short time,"
Sir Cyril told the conference yesterday.
"Order and discipline, with a high level of attendance. The school opened at 7.30am, with breakfast available, and stays open until 6pm. There is a very good programme of extra-curricular activities, including sports. There is a huge emphasis on acquiring literacy and numeracy skills."