[1] His novel Floodland (2001) won the Branford Boase Award and The Dark Horse (2002) was shortlisted for the Guardian Children's Fiction Prize.
[3] His mother had once worked in Machynlleth at the Centre for Alternative Technology; the area was the setting for Susan Cooper's fantasy series The Dark Rising, and Sedgwick called those books influential for him.
[3] Floodland tells the story of Zoe, who lives on her own on an island that used to be part of England before global warming caused the seas to rise.
Publishers Weekly said that "Despite some page-turning chapters, Zoe and her story lack the credibility to sustain readers through the contradictory themes and sometimes unimaginative prose.
[3] In 2013 he released Dark Satanic Mills, a graphic novel written in conjunction with his brother Julian Sedgwick and illustrated by John Higgins.
[3] His 2015 book The Ghosts of Heaven, a work of young adult fiction consisting of four loosely connected parts combined into an "intriguing" novel, according to Sarah McCarry writing for The New York Times.
[3] Sedgwick taught creative writing at Bath Spa University as a writer in residence from 2011 through 2014 and wrote reviews for the Guardian newspaper.