Nihal Arthanayake presents a portrait of contemporary Britain in an epoch of terror.
It's part of contemporary life we experience but are ashamed to discuss.
But Nihal Arthanayake wants to talk it: about the things that are left unsaid. The empty chair next to a person from an ethnic minority on a packed bus or train. That anxious glance, or downright hostile gaze.
Nihal hears from people from around Britain about how the threat of terrorist attacks is making us all frightened of each other's shadows; charting the emotional landscape of Britain at a time of heightened anxiety and distrust.
Olaoluwa Opebiyi was removed from a plane by armed police after a fellow passenger reported him to cabin crew for acting suspiciously.
Karan Chadda shaved off his hipster beard when people started avoiding him.
Tomiwa Folounso tells us that she feels guilty for being wary of young Asian men, when she too has experienced prejudice in the past.
How do manage these fears?
Some of the people we spoke with in this programme have asked to remain anonymous, but we'll hear from Steve Reicher, a Professor of Social Psychology at St Andrews University and Les Back, Professor of Sociology at Goldsmiths, University of London. We join writer Iain Sinclair as he takes Nihal on a walk through history around the City of London.
Nihal also speaks with Robin Goodwin from Warwick University who has been measuring people's responses to terrorist attacks, from 9/11 right up until the November attacks in Paris in 2015. Is terrorism changing the way we relate to each other?
Producer: Caitlin Smith.