Upon graduating in 1953 Segar moved to London and began working in advertising for Horatio Myer & Co. Ltd, then SH Benson.
[2] For 30 years, Segar worked as an illustrator and graphic designer for the Economist Intelligence Unit in London.
From 1961 to 1970 Segar designed and illustrated the monthly Anarchy magazine, edited by Colin Ward and published by Freedom Press.
Ward gave Segar significant freedom in his design of each issue, though working to a tight deadline.
[1] Segar retired to Saltwood in Kent, followed by Pershore in Worcestershire, though he continued illustrating books.