If you’ve been gripped by Jed Mercurio’s conspiracy-packed BBC series Bodyguard, then you’re not alone. More than 11 million viewers have been hungrily tuning in to follow PC Budd (aka actor Richard Madden) as he discovers who killed controversial Home Secretary Julia Montague, played by Keeley Hawes. From Andrew Marr cameos to faked Wikipedia pages, believability has been at the heart of the thriller’s success. The person to thank for all that spine-tingling detail is graphic designer Matthew Clark, who created every single graphic element you see in the series, from branding for the Police (including PC Budd’s badge) to car chase maps, PNC search results, forensic evidence photos, police forms, protest banners, restaurant menus, snaps of Keeley Hawes and ex-PM David Cameron, not to mention hours of CCTV footage. Just before the dramatic finale on Sunday, we went behind the scenes with Matthew to talk about meticulous world-building, designing on set and late nights.