‘Blue Lights’ Season 4 Returns to Patrol BritBox in November
As 'Blue Lights' Season 4 arrives in the U.K., BritBox is preparing to debut the series in the U.S.
This is the second autumn in a row that BritBox has made a temporary deal with HBO to feature some of its best shows on the high-end streaming service under the header “The Best of British TV by BritBox.” While most titles in the collection are the same as last year, at least one show has gained a new season: Blue Lights. Season 3 debuted in November 2025 (while we were on hiatus), a month after the collection left HBO.
To no one’s surprise, BritBox added Season 3 to its temporary HBO lineup for the 2026 offerings, and for the same reason: Season 4 of Blue Lights will debut on BritBox only days after the collection exits HBO again. As the Season 4 premiere gears up in the U.K. for an end-of-September debut, BritBox is preparing to bring the series across the pond as soon as the finale airs, with confirmation that the new season will arrive in the first half of November.
The new season also promises that, even though Season 3 pulled more punches than it maybe should have, a reckoning is coming. After three years on the job in Belfast, our rookies aren't as green as they once were. More importantly, some of the things they were told (and still believe) were lies, and the sooner our leads accept that reality – and face the truth about their fellow officers – the better off everyone will be.
Here’s the Season 4 synopsis:
Three years into their jobs as response officers, Constables Grace Ellis, Tommy Foster, and Annie Conlon are operating at their limit, facing a new threat on the streets that the police can barely control. Meanwhile, 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. 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.
As always, our main quartet of cops includes Siân Brooke as Grace, Martin McCann as Stevie, Katherine Devlin as Annie, and Nathan Braniff as Tommy. They are once again joined by Joanne Crawford (Outlander: Blood of My Blood), Andi Osho (The Sandman), Frank Blake (Say Nothing), Dearbháile McKinney (Kneecap), Andrea Irvine (Call the Midwife), and Abigail McGibbon (Ballywalter). Season 3 additions Cathy Tyson (Dune: Prophecy) and Michael Smiley (Bad Sisters) also return.
Season 4 will also feature Richard Dormer (COBRA) and Jonathan Harden (Time), reprising their respective roles as Gerald Cliff and Inspector Jonty for the first time since Season 1. Hannah McClean (Sick Note) will also return as solicitor Jen Robinson after sitting out Season 3.
Series creators Declan Lawn and Adam Patterson once again co-wrote all six episodes, with director Angela Griffin returning to split helming duties with Sam O’Mahoney (The Wise Guy), with Brendan Mullin producing. Lawn and Patterson co-created the series with Stephen Wright; the three executive produce alongside Louise Gallagher and Nick Lambon for the BBC.
Blue Lights Season 4 debuts on BBC One and iPlayer on Tuesday, September 29, 2026. The series will follow on BritBox starting Thursday, November 12, 2026, and stream one episode a week through mid-December. We expect all episodes to be available to stream on November 12 for BritBox Premier subscribers, and we will confirm as soon as we hear back.
Blue Lights
Seasons 1 through 3 are streaming on BritBox.
