Blue Lights fans can start celebrating – the BBC has officially confirmed series 4 of the hit police drama is in production, and has now shared some intriguing details about what’s coming in the 2026 episodes.
Two words. Gerry Cliff.
The gritty Belfast-set series returned at the end of September 2025 with its third run, delivering the same mix of tension, danger and dark humour that hooked viewers from the start. The BBC will follow it up with series 4 later this year, continuing the story of the city’s frontline officers.
So what lies ahead? Here’s everything we know so far about Blue Lights series 4 on BBC One – with no spoilers for series 3.
Is there a series 4 of Blue Lights?
After Blue Lights series 3 matched the strength of the first two runs, the BBC moved quickly to commission more.
BBC One has confirmed it has recommissioned the Belfast police drama for a fourth series. With its consistent quality so far, the show looks capable of running for years. It has already avoided the infamous second-series slump that caught out shows like The Last of Us, Squid Game and Nine Perfect Strangers.
As long as co-creators Declan Lawn and Adam Patterson maintain this standard of writing, Blue Lights shows no signs of slowing down.
Series 1 also made a powerful impact, landing in the top 10 new drama series of 2023 across all broadcasters and streamers. It quickly established itself as one of Northern Ireland’s biggest drama hits.
‘A gripping drama about ordinary people doing an extraordinary job’
The BBC has ordered at least one more six-part series of the critically acclaimed Belfast-based police drama.
When announcing the recommission, the broadcaster described Blue Lights as “an authentic, gripping and darkly funny drama about ordinary people doing an extraordinary job”.
Series 1, which aired in 2023 to critical acclaim, introduced three PSNI probationary recruits Annie, Tommy, and Grace. Together with more experienced frontline response cops, they worked one of the hardest beats in the UK – Belfast, a city with unique pressures and dangers.
Series 2, which aired in 2024, followed the trio a year later. By then, they had settled into the job but faced a drug-fuelled crime wave that dragged them into a loyalist estate.
Series 3 arrived in 2025 and picked up two years into their careers. Grace, Annie and Tommy had adjusted to life under the blue lights, but the risks only increased.
The synopsis revealed: “Their work takes them into a sinister world hidden behind the veneer of middle-class life, the world of the accountants and lawyers who facilitate organised crime.
“The old political and criminal order has gone and a new global gang rule Belfast, bringing danger closer to home for our officers than ever before.”
How many episodes is Blue Lights series 4?
Series 4 will run for six hour-long episodes.
The show will stick to the same format it has used since the start.
How can I watch Blue Lights?
Viewers can stream Blue Lights series 1 to 3 now on BBC iPlayer.
That gives fans 18 hours of gripping police drama to catch up on.
Who will return in the cast?
BBC One has confirmed the cast for series 4 of the BAFTA award winning drama – and one returning character will surely cause you do to a happy (if confused) dance.
Richard Dormer will return as Gerry Cliff for a special episode that aims to “answer important questions from the past”. Fans will remember that organised criminals tragically murdered his character in the first series, an event that still affects the team, especially his widow Sandra.
Series 4 follows the murder trial of Gerry Cliff. The BBC says the “murder trial of Gerry Cliff exposes a dangerous and long-buried secret that leads to chaos both inside the police, and across the criminal underworld”.
The new episodes also bring back familiar faces, including Hannah McClean and Jonathan Harden as disgraced former Inspector Jonty.
Nick Lambon, BBC Drama Commissioning Editor, UK & Northern Ireland, said: “Gerry Cliff was such an integral part of series one so to have Richard Dormer back alongside our talented cast is a dream come true. We are over the moon to be back filming in Belfast, and with so many twists and turns in store, fans of Blue Lights have plenty to look forward to.”
Also returning in the cast are regulars, including:
- Siân Brooke as Grace Ellis.
- Martin McCann as Stevie Neil.
- Katherine Devlin as Annie Conlon.
- Nathan Braniff as Tommy Foster.
- Joanne Crawford as Helen McNally.
- Andi Osho as Sandra Cliff.
- Frank Blake as Shane Bradley.
- Dearbháile McKinney as Aisling.
- Abigail McGibbon as Tina.
- Dearbháile McKinney as Aisling.
- Andrea Irvine as Nicola.
What’s the plot of Blue Lights series 4?
Now three years into their careers as response officers, Grace Ellis, Tommy Foster and Annie Conlon find themselves operating at full stretch as a new threat grips the streets – one the police struggle to control.
The synopsis says: “As they grapple with big decisions about their future, Grace, Tommy and Annie must find the courage to face the greatest threat they have ever encountered: the truth.”
Co-creators Declan Lawn and Adam Patterson said: “We’re very excited to bring this series of Blue Lights to audiences. It 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. We can’t wait to start filming it!”
The BBC has already teased some “brilliant ideas” for the next chapter.
BBC Director of Drama Lindsay Salt said: “We were bowled over by the reaction to Blue Lights and I’m really pleased to be confirming our commitment to bring more series of our beloved Belfast drama to air.
“Adam and Declan have brilliant ideas about where to take the characters next and I can’t wait for viewers to see what’s in store.”
The BBC will announce more details about the cast and plot for series 4 of Blue Lights in due course.
Read more: From Blue Lights to Celebrity Traitors, these are the best TV shows of 2025