First broadcast: on BBC One HDLatest broadcast: on BBC One Wales
The Skripals and DS Bailey fight to survive, and Tracy and the emergency services try to locate the source of the nerve agent to prevent further casualties.
First broadcast: on BBC One HDLatest broadcast: on BBC One Northern Ireland HD
CID officer Nick Bailey’s condition worsens as Tracy struggles to protect local residents against the numerous deposits of Novichok being found across the city.
