The Geoffrey Chaucer School in Elephant and Castle - designed in 1958 by the architect behind the Barbican - has been earmarked by the heritage body as one of the finer examples of post-war school buildings in the capital.
The school will make way for the Future Systems-designed Globe Academy, which will bring together the existing Chaucer Technical College and Joseph Lancaster Primary School.
However, C20 will be somehwat comforted by the decision of the council and Future Systems to keep the Chaucer school's distinctive pentagon building.
Lucy Heller, managing director of Absolute Return for Kids, which sponsors the school, said: 'We are delighted that all the planning applications were approved on Tuesday. We can at last look forward to creating buildings that match both schools' aspirations for the future.'
The move follows the news that another Chamberlin Powell and Bon building, Milton Court in the Barbican, could make way for a replacement designed by David Walker Architects ( David Walker's Barbican tower scheme rejected ).