The BBC has unveiled a first-look teaser for the highly anticipated fourth season of its hit police drama, Blue Lights. With the Northern Ireland-set series scheduled to return to our screens this autumn, now is the perfect time to catch up on the first three seasons, all of which are available to binge-watch on iPlayer.

The acclaimed drama has garnered widespread praise from critics and has even been hailed by viewers as “heart-pounding” and superior to another popular BBC police series, Line of Duty. Renowned for its riveting storylines, high-stakes tension and gritty social realism, this authentic police drama is guaranteed to keep you glued to your screen.

© CREDIT LINE:BBC/Two Cities Television/Matthias Clamer

Season 4 teaser trailer

In the newly released clip, Constable Shane Bradley (Frank Blake) finds himself on a mission to improve Blackthorn’s crime statistics, a task that leads to a rather humorous encounter with an elderly driver named David.

“Do you know why I pulled you over today, Sir?” he asks. “You crossed in front of us there without indicating. Have you had any alcohol today?”

© BBC/Two Cities Television

“No,” the driver replies, revealing that the last time he had a drink was at Christmas in 2003, when he mistakenly drank an alcoholic beverage thinking it was grape juice.

Keep reading to find out all we know about season four.

What to expect from season 4

The drama follows three rookie police officers as they navigate the intense pressures of policing the streets of Northern Ireland’s capital.

Season four follows the murder trial of Gerry Cliff, who was killed in the first season of the crime drama.

© BBC/Two Cities Television

The synopsis for season four reads: “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.”

© CREDIT LINE:BBC/Gallagher Films/Two Cities Television

Declan Lawn and Adam Patterson, co-creators and co-writers, said the new season “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.”

Who stars in season 4?

Siân Brooke (Sherlock, Trying) leads the cast as Grace, alongside Martin McCann (Trespasses, Hostage) as Stevie, Katherine Devlin (The Day Of The Jackal, Vikings) as Annie, Nathan Braniff as Tommy and Frank Blake (Say Nothing, Normal People) as Shane.

© BBC/Two Cities Television

Richard Dormer (The Day of the Jackal, Game of Thrones), who played Gerry Cliff in series one, reprises his role, alongside Hannah McClean (Malpractice) as solicitor, Jen Robinson and Jonathan Harden (The Rainmaker, Time) as disgraced former Inspector, Jonty.

Blue Lights returns to BBC One and iPlayer this autumn. All three seasons are available to stream on BBC iPlayer now.