Blue Lights Season 4: BBC One Air Time, Full Cast, Filming Locations & what happened in season 3

Blue Lights Season 4 starts tonight.

 UK Premiere Date: Tuesday, 29 September 2026

 Air Time: 9:00 PM BST

 TV Channel: BBC One

 UK Live Stream & Catch-Up: BBC iPlayer (Full Series Boxset)

 US Streaming Platform: BritBox US

 Episode Count: 6 Episodes

BAFTA-winning police drama Blue Lights makes its long-awaited return to screens for Series 4 on BBC One and BBC iPlayer. Created and written by Declan Lawn and Adam Patterson, the Belfast-set hit returns as response officers face high-stakes turmoil on the front lines.

Here is everything to know about Blue Lights Season 4, including broadcast details, cast updates, plot teasers, filming locations, and international streaming access.

How to Watch Blue Lights Season 4 in the UK & US

 In the UK: Blue Lights Series 4 premieres on BBC One at 9:00 PM on Tuesday, 29 September. The entire six-episode series drops simultaneously on BBC iPlayer as a boxset at 9:00 PM for viewers wanting to binge the season.

 In the US: American viewers can stream Blue Lights exclusively on BritBox. Seasons 1–3 are currently available to watch on BritBox US, with Season 4 following its UK broadcast.

Season 3 Recap: Where Did We Leave Off?

Season 3 followed the response section down a dark path as a routine drug arrest involving young dealer Sandy McKnight unraveled a massive criminal conspiracy stretching into Belfast’s elite. The section faced personal tragedy and moral dilemmas: Aisling dealt with traumatic fallout from a devastating car crash, while Grace and Tommy pushed professional boundaries to protect those targeted by escalating threats. The season ended with shifting loyalties, leaving the team physically exhausted and questioning their futures within the PSNI.

What’s Coming Up in Season 4?

Set six months after the harrowing events of Season 3, Series 4 sees Grace, Tommy, and Annie standing at critical crossroads as they struggle with major decisions about their futures in the force.

As new threats emerge on Belfast’s streets, personal and professional boundaries blur even further. Creators Declan Lawn and Adam Patterson have teased “plenty of twists and turns,” with the BBC promising a deeply emotional run that puts the officers’ resilience to the ultimate test.

Blue Lights Season 4 Cast

The core response team returns alongside major recurring cast members and returning favorites:

 Siân Brooke as Grace Ellis

 Katherine Devlin as Annie Conlon

 Nathan Braniff as Tommy Foster

 Martin McCann as Stevie Neil

 Andi Osho as Sandra Cliff

 Dearbháile McKinney as Aisling

 Richard Dormer returning to the series

Filming Locations

Blue Lights is filmed on location across Belfast and Northern Ireland with support from Northern Ireland Screen. Key filming spots across the series include:

 Monkstown & Dundonald: Used for residential response calls and estate scenes.

 Belfast City Centre: Features prominently during high-speed vehicle pursuits and street patrols.

 Titanic Quarter Studios & East Belfast: Used for indoor police station hub sets (Blackwood Police Station) and tactical response staging.

Critical Success & Award Winning Record

Since launching in March 2023, Blue Lights has established itself as one of the BBC’s flagship police dramas. Garnering critical praise for its authentic portrayal of frontline policing, the series averages over 4.3 to 4.8 million viewers per episode in the UK. The show earned a BAFTA TV Award nomination and won at the Royal Television Society (RTS) Awards, making Series 4 one of the most anticipated television returns of the year.

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