Blue Lights Series 4: Everything We Know So Far

The sun is still shining down on much of the UK after that record-breaking heatwave, which means one crucial thing for TV fans: there really isn’t very much to watch. Now, we shouldn’t be ungrateful: it’s a rare gift to see the sun so consistently without jetting off to a warmer country. But, if you are anything like me, you are probably already getting a little tired of the guilt that floods the body when you snub the long balmy evenings for a night on the sofa. That’s my happy place: a gloomy evening snuggled up on the sofa with a blanket, rain pattering on the windows, a thrilling new drama beaming out from the telly.

One of my favourite genres is British crime, which has become almost synonymous with autumn in a TV sense. This is when the BBC, ITV, Channel 4 and even the likes of Netflix haul their grimmest, goriest tales from the locker and splash them across the small screen.

One of the best examples in recent years has to be Blue Lights, the Northern Irish police procedural drama created and written by Declan Lawn and Adam Patterson, which premiered in 2023. In an industry with ever-widening gaps between seasons, when it comes to Blue Lights, we’ve been blessed with a new series every year. Flash forward to 2026, and that means series 4 is en route. Set to air on BBC One this autumn, here’s everything you need to know.

(BBC)

Blue Lights Series 4: Plot, Cast, Release Date & More

After the stonking success of the first series, the BBC ordered a double renewal of Blue Lights in February 2024, confirming series three and four would be zooming onto our screens in the future before series 2 had even aired. The BBC’s director of drama Lindsay Salt said she had been ‘bowled over by the reaction to Blue Lights‘.

Backdropped by the complex politics of Belfast, Northern Ireland, Blue Lights centres on three new PSNI probationary recruits as they navigate the uniquely complex landscape. This includes Siân Brooke as 40-something former social worker Grace Ellis, Martin McCann as the inept but desperate to prove himself Stevie Neil, and Katherine Devlin as Annie Conlon, a young woman who struggles with the fact that her chosen path may mean having to leave everything she’s ever known behind.

Since those early days, our trio of coppers have grown up and grown stronger in their roles. Series 2 opens with the trio a year into the job, while series 3 saw them continuing to navigate Belfast’s rocky terrain.

Grace Ellis (SIÂN BROOKE) in Blue Lights series 3. (BBC)

What Will Happen In Series 4?

The BBC is keeping schtum, but co-creators and co-writers Declan Lawn and Adam Patterson tease Blue Lights series 4 ‘reveals a lot of dark secrets, examines what justice looks like in Belfast today, and ties together the past, present, and futures of Grace, Annie and Tommy in an action-packed story’.

Speaking to C&TH last year, star Katherine Devlin added: ‘We’re back in the world of drug dealing but they’re honing in on white collar crime. The glitz and glam of a boujee private members club with a seedy history.’

We also know there will be a bit of a throwback: series 1 star Richard Dormer will return to his role as Gerry Cliff alongside disgraced former Inspector Jonty (Jonathan Harden) in an episode that will answer some of the past’s lingering questions.

Annie Conlon (KATHERINE DEVLIN) & Sandra Cliff (ANDI OSHO) in Blue Lights series 3. (BBC)

Is There A Trailer?

No trailer, but the BBC has revealed a ‘first look’ clip, which shows Constable Shane Bradley (Frank Blake) stopping an elderly driver in a bid to improve Blackthorn’s crime statistics. Watch it below.

The Cast

• Siân Brooke as Grace
• Martin McCann as Stevie
• Katherine Devlin as Annie
• Nathan Braniff as Tommy
• Frank Blake as Constable Shane Bradley
• Richard Dormer as Gerry Cliff
• Hannah McClean as Jen Robinson
• Jonathan Harden as Jonty
• Trevor Gill as David
• Rosamund Monteith as Imelda
• Joanne Crawford as Helen McNally
• Andi Osho as Sandra
• Abigail McGibbon as Tina
• Dearbháile McKinney as Aisling
• Neil Keery as McCloskey
• Andrea Irvine as Nicola
• Cathy Tyson as Dana Morgan
• Michael Smiley as Paul ‘Colly’ Collins

Tommy Foster (NATHAN BRANIFF) in Blue Lights series 3. (BBC)

Release Date

No specific date just yet, but we are told Blue Lights series 4 will be coming to BBC iPlayer and BBC One this autumn. The series will be made up of six episodes.

The first three series are available to stream now on BBC iPlayer.