Riley has written and drawn many best-selling cartoon books, including
The Book of Bunny Suicides (2003) and its sequels, and
Great Lies To Tell Small Kids (2005). From 2002 until February 2010 he drew a weekly comic strip called
Roasted in
The Observer Magazine, a collection of which was released in book form in 2007. Riley also publishes the King Flashypants series of children's books
. With
Kevin Cecil, his best friend since they attended
Aylesbury Grammar School, he created and wrote the sitcoms
Year of the Rabbit for Channel 4 and IFC,
The Great Outdoors for
BBC Four,
Hyperdrive for BBC Two and
Slacker Cats for the ABC Family Channel. Their other television work includes
Veep (for which they each won an Emmy in 2015 in the Outstanding Comedy Series category),
Black Books, the
Comic Relief one-off special
Robbie the Reindeer, for which he and Cecil won a
BAFTA in 2000,
Little Britain, Tracey Ullman's Show,
Trigger Happy TV,
So Graham Norton,
Smack the Pony,
The Armando Iannucci Shows,
Harry and Paul,
Big Bad World,
Come Fly With Me, and
Spitting Image. The
Radio Four panel game they wrote with
Jon Holmes and
Tony Roche,
The 99p Challenge, ran for five series from 2000. They wrote for the Touchstone animated feature
Gnomeo and Juliet, and its sequel
Sherlock Gnomes. Riley has co-written two TV adaptations of
David Walliams books:
Gangsta Granny and
The Boy in the Dress. ==Screenwriting credits==