Blue Lights season four premieres with Gerry Cliff flashbacks

The fourth season of the Belfast-set police drama Blue Lights premiered on BBC One on September 29, 2026, returning its central response officers to the screen and bringing back Richard Dormer as Gerry Cliff in flashbacks tied to the character’s murder trial. The new season follows constables Grace Ellis, Tommy Foster and Annie Conlon as they face a new threat on the streets while weighing decisions about their futures. Season descriptions say the trial exposes a long-buried secret with consequences inside the police and across the criminal underworld. The plot details come from the programme’s promotional synopsis and cast accounts. Gerry was killed in the first season. Dormer’s return is through flashbacks, according to descriptions of the new episodes. The trial storyline revisits the character’s past and is intended to address the case surrounding his death. Co-creator Adam Patterson said the passage of time in the story made it possible for the criminal case to reach a conclusion and that revisiting it allowed the narrative to give the story further closure.