London County Council commissioned Basil Spence & Partners, in the early 1950s, to design additional accommodation to allow the school to increase capacity from 600 to 1140 students and to merge with Shackleton School to become a comprehensive school.

This took place in 1956 on completion of the new six-storey, E-shaped, classroom block, on which work had begun in 1954.

In each year there are 8 tutor groups, named for the letters in SYDENHAM.

The current headmistress is Ms Emma Wijnberg.

In the last OFSTED inspection, Sydenham School was graded as 'good with outstanding features '.