Scripting comics together since 2003 the duo have written for the likes of 2000 AD, Channel 4 Education, Dark Horse, DC Comics, Dynamite Entertainment, Electricomics, IDW, and Self Made Hero.
They have written established characters such as Doctor Who (The Whispering Gallery, 2008 with Ben Templesmith) and Sherlock Holmes (The Trial of Sherlock Holmes, 2009 with Aaron Campbell, The Liverpool Demon, 2012 with Matt Triano, and The Vanishing Man, 2018 with Julius Ohta), as well as creating their own including Brit-Cit Psi Division, Judge Lillian Storm (Storm Warning, 2015/2018 with Tom Foster and Jimmy Broxton). Their Middle Grade GN Conspiracy of Ravens (with Sally Jane Thompson) was published by Dark Horse in 2018.
Together Moore & Reppion have faithfully adapted notable works by Lewis Carroll (The Complete Alice, 2010), H. P. Lovecraft (The Shadow Over Innsmouth, 2012), Bram Stoker (The Complete Dracula, 2009), and M. R. James (Ghost Stories of an Antiquary Vol 1 & 2, 2016/2017) into comics and graphic novels.
In 2020 they scripted a series of short online comics for Nesta's Minds and Machines project - exploring the role Artificial Intelligence might play in our near future.
Moore & Reppion were consulting writers for some of the mysteries featured in Frogwares Games multi-platform adventure Sherlock Holmes - Crimes & Punishments, 2014.