The Last Detectives: Inside the BBC’s New Welsh Crime Drama

A murdered university professor, baffling investigations and two longtime friends searching for a fresh start are at the heart of The Last Detectives, the BBC’s upcoming six-part crime drama set along the Welsh coast.

Starring Mark Lewis Jones as DI Glyn Walsh and Steffan Rhodri as DS Sion Dearden, the series follows two experienced detectives whose personal lives have taken difficult turns. When they reunite to investigate a string of unusual crimes in the seaside town of Tenby, their shared history becomes both a source of strength and a reminder that rebuilding a life is rarely straightforward.

Blending intricate mysteries with humour, warmth and a story about friendship later in life, The Last Detectives could appeal to fans of Shetland and character-driven British crime dramas.

What Is The Last Detectives About?

Set in Tenby, West Wales, the drama centres on DI Glyn Walsh and DS Sion Dearden, two seasoned officers whose professional partnership is built on years of friendship.

The story begins when Glyn returns earlier than expected from bereavement leave. Before long, he and Sion are assigned the murder of a celebrated university professor. What initially appears to be a conventional homicide investigation draws them into the unfamiliar world of the local university, where they must work through the evidence to identify the killer.

But the professor’s death is only the beginning. As the detectives take on further cases, they encounter crimes that are far from straightforward.

According to the BBC’s official synopsis, one investigation concerns a local head teacher who is poisoned before inexplicably drowning while wild swimming. Another revolves around a puzzling case of mistaken identity during a triathlon.

Each mystery unfolds over two episodes, giving Glyn and Sion time to pursue leads, confront unexpected developments and uncover secrets beneath Tenby’s peaceful exterior.

Their work is complicated by the fact that they must also navigate the challenges of living and working under the same roof. Both men have personal difficulties to overcome, but their instinctive understanding of one another may prove invaluable when the cases become increasingly complex.

Alongside the two lead detectives, the team includes DC Remy Jones, played by Bethan Mary-James, DC Neil Miller, and forensic biologist Professor Pamela Thomas, portrayed by Julie Graham.

Rather than concentrating exclusively on solving murders, The Last Detectives also explores how friendship and shared experience can help people rediscover their purpose at a difficult stage of life.

What Has the Creative Team Revealed?

Welsh-born Matthew Barry created, wrote and executive produced the series. His previous work includes The Guest.

Speaking to the BBC, Barry expressed his excitement about working with Quay Street Productions and the broadcaster again. He described the drama as a story about finding friendship and meaning later in life, told through the familiar framework of a police procedural.

He also shared his hope that viewers would become invested not only in Glyn and Sion but in Tenby itself.

Producers Davina Earl and Nicola Shindler of Quay Street Productions have similarly praised Barry’s writing, highlighting the relatable characters, warmth, humour and inventive mysteries that shape the series.

They also expressed confidence in the casting of Mark Lewis Jones and Steffan Rhodri, believing the pair were well suited to portraying the distinctive bond between the two detectives.

That relationship is central to the show’s identity. The investigations provide the suspense, while the friendship between Glyn and Sion connects the individual cases and gives the series a more personal dimension.

Who Stars in The Last Detectives?

The six-part drama brings together several familiar faces from British television, with Mark Lewis Jones and Steffan Rhodri leading the cast.

• Mark Lewis Jones (The Crown) as DI Glyn Walsh

• Steffan Rhodri (Keeping Faith) as DS Sion Dearden

• James Bamford (Masters of the Air) as DC Neil Miller

• Catherine Ayers (The Guest) as Chief Superintendent Melanie Morris

• Bethan Mary-James (Death Valley) as DC Remy Jones

• Julie Graham (This City Is Ours, Time) as forensic biologist Professor Pamela Thomas

Jones and Rhodri play two experienced officers whose longstanding friendship shapes their approach to detective work. Both characters are dealing with personal challenges, and their partnership gives them an opportunity to find direction again while investigating increasingly unusual crimes.

Graham’s Professor Pamela Thomas contributes specialist forensic expertise, helping the team interpret evidence and make sense of complex cases. The wider police team also plays an important role as the detectives work towards uncovering the truth.

When Will The Last Detectives Be Released?

The BBC has not yet announced an official premiere date for The Last Detectives.

Filming has taken place in Tenby, Cardiff and along the South Wales coastline. These locations give the drama a distinctly Welsh identity, with picturesque seaside views providing a striking contrast to the disturbing crimes at the centre of the story.

The coastal setting also helps establish the atmosphere of a close-knit community where familiar surroundings may conceal unexpected secrets.

Until the BBC confirms its release plans, viewers will have to wait to find out when the six episodes will arrive.

What to Watch While You Wait

If The Last Detectives sounds appealing, there are other crime dramas worth exploring in the meantime.

The Island

Fans of Shetland and The Loch may want to try The Island, a BBC drama starring Sorcha Groundsell as Family Liaison Officer Kat Crichton.

Kat becomes involved in a harrowing murder investigation, placing her at the centre of a tense mystery filled with difficult questions and complicated criminal cases.

Its focus on police work and the people affected by serious crime may appeal to viewers who enjoy character-driven British mysteries.

Murder in a Small Town

Another option is Murder in a Small Town, starring Rossif Sutherland as big-city detective Karl Alberg.

Seeking a quieter life, Karl moves to an idyllic harbour town. However, the peaceful surroundings offer little escape from his profession, and he soon finds himself investigating murders in a community that is not nearly as tranquil as it appears.

The contrast between the picturesque setting and the crimes unfolding within it makes the series a natural choice for anyone drawn to the coastal atmosphere of The Last Detectives.

A New Mystery on the Welsh Coast

With its unusual murder cases, atmospheric Welsh locations and a central partnership shaped by years of friendship, The Last Detectives promises a different take on the traditional police procedural.

The series combines the challenge of solving complex crimes with a more intimate story about two men trying to rebuild their lives. For viewers who enjoy British detective dramas where character relationships matter as much as the mysteries themselves, it could be one to keep on their radar.

For now, the BBC’s official release date remains unconfirmed.