Netflix’s Four-Part Collateral Is a Gripping London Detective Thriller With a Stellar British Cast

One seemingly straightforward murder sends a detective into a far wider web involving immigration, politics, the church, the military and the police in Collateral, a tightly constructed four-part thriller available to stream on Netflix.

Originally released in 2018, the drama brings together an impressive British cast led by Carey Mulligan, alongside Nicola Walker, Billie Piper and John Simm. With only four episodes, it offers the kind of compact crime story that can easily be finished over a weekend.

One murder opens the door to a much bigger story

Set in contemporary south London, Collateral begins with the killing of a pizza delivery driver by an unidentified figure.

DI Kip Glaspie, played by Mulligan, takes charge of the investigation and quickly discovers an important detail: the restaurant’s usual delivery driver had been replaced that evening by Abdullah Asif, a Syrian refugee portrayed by Sam Otto.

As Glaspie digs deeper, what initially appears to be an isolated killing begins connecting people from very different corners of London.

Among them is a local Labour politician played by John Simm, his ex-wife Karen Mars, portrayed by Billie Piper, and Nicola Walker’s vicar Jane Oliver.

Rather than simply building toward the identity of the killer, the drama gradually widens its focus to examine the circumstances and institutions surrounding the crime.

A ‘whydunnit’ rather than a traditional mystery

Playwright David Hare, who wrote the series, described Collateral as “not a whodunnit, a whydunnit.”

Instead of making the killer’s identity the only driving mystery, the story is concerned with understanding who is involved, what connects them and why events have unfolded as they have.

Hare explained that illegal immigration and detention centres become increasingly important as the series progresses, alongside storylines involving the church, Parliament, the army and police.

That approach gives Collateral a distinctly political dimension while still retaining the tension of a detective thriller.

Viewers praised its gripping story

The series received positive reviews following its original release. The Guardian awarded it four stars and highlighted its political dimension, while Collateral achieved a 79% Tomatometer score on Rotten Tomatoes.

Audience reactions have also praised its ability to maintain tension across its short run, with one viewer describing the series as “gripping to the end.”

Another singled out its female characters for praise, arguing that the drama avoids many of the familiar stereotypes associated with women in crime television and instead gives them greater vitality and complexity.

With Carey Mulligan at the centre of the investigation and Nicola Walker, Billie Piper and John Simm helping anchor the interconnected storylines around her, Collateral combines a murder investigation with a broader examination of the people and institutions caught in its aftermath.

Collateral is available to stream on Netflix.