Born in Norfolk but raised in Wales, Thomas doodled his way through childhood until they let him into Norwich School of Art and Design. He then studied illustration at Anglia Ruskin University, Cambridge. His first commissioned work was the cover illustration for a then unknown book called Harry potter and the Philosopher's Stone by J. K. Rowling.
Since then Thomas has written and Illustrated many children's picture books, and even written a few for others to illustrate. He lives in Normandy, France, where he shamelessly steals story ideas from his two little boys, Max and Benjy.