There are few shows I’ve watched more compulsively than the epic BBC spy series MI-5 (2002-2011). A few months ago I casually backgrounded a couple of early episodes only to find myself getting sucked into a full-run marathon. It was an interesting rewatch, holding up both worse and better than I recall it: worse in that its earliest seasons aren’t as strong as I remembered, better in that its later ones aren’t as disappointing. One opinion that didn’t change, though, is that the series’ sixth season is its best; an astonishingly late peak that colors my impression of both the show’s earliest steps and final moments.
The series revolves around “Section D” of the British Home Security Services, MI-5, a team of crack agents tasked with the protection of the British homeland from external threats. In every episode, Section D, led by its scheming leader Harry Pearce (Peter Firth), thwart terrorist threats, analyze intelligence, work sources in the field, respond to political events, and more. The structure throughout is very “crisis-of-the-week,” with each episode focused on resolving an urgent situation. But it’s also an evolving series, each mission contributing to a larger story: characters change, the makeup of the team shifts, reputations are built or destroyed, and series lore accumulates. It’s a fine balancing act of the familiar and the novel, the lure of a comfortable milieu tinged with the ever-present threat of drastic disruptions, which come on a regular basis.
The original, core team consists of promising young section chief Tom Quinn (Matthew Macfadyen), viperous senior analyst Tessa Phillips (Jenny Agutter), and two junior case officers, Zoe Reynolds (Keeley Hawes) and Danny Hunter (David Oyelowo), as well as a bevy of administrative and support officers, the most notable of which is surely avuncular tech genius Malcolm Wynn-Jones (Hugh Simon). This crew — which should include brilliant analyst Ruth Evershed (Nicola Walker), introduced in season two — is perhaps the series’ most accessible and human. In retrospect, the early seasons seem much more interested in integrating the high stakes suspense of security work with the troubled personal lives of the agents, especially Tom, Zoe, and Danny. In these years, Hawes and Oyelowo are both particularly likable as idealistic young hotshots, trying to balance their better natures against the ugly realities of the business, a conflict that comes to a powerful head in the superb season three outing “Love and Death.” The human element makes this team the warmest, but perhaps also the series’ least formidable, more prone to emotional lapses and rookie mistakes than some of the badasses and daredevils that would follow in their wake.
Season one starts well, but doesn’t really catch fire until the fourth episode, “Traitor’s Gate,” a terrific espionage puzzler about a possible rogue agent named Peter Salter (Anthony Stewart Head). Here, the show reveals itself as something more than just “the British 24,” incorporating more classic espionage elements, politics and personalities in the vein of Tinker Tailor Soldier Spy and The Sandbaggers. At its best, MI-5 balances action, intrigue, politics, and personalities in a careful blend, and “Traitor’s Gate,” the episode that secured my addiction, gets the mix just right.
The first time around, I remember lamenting the individual departures of Tom, Zoe, and Danny in season three. On the rewatch, though, I found myself looking forward. The introduction of a more charismatic, traditional leading man in Adam Carter (Rupert Penry-Jones) — a character I originally resisted — would end up being the first building block of an MI-5 “dream team,” which starts to come together in seasons four and five with the arrival of new junior officers Zafar Younis (Raza Jaffrey) and Jo Portman (Miranda Raison). (Jo’s recruitment episode, “The Book,” is probaby my favorite single episode, and the beginning of my not-very-secret love affair with this character, who serves as the heart of the team for much of its run.) The cast is further strengthened in season five with the arrival of the venomous Ros Myers (Hermione Norris), who enters the series as a love-to-hate character. Indeed, she’s so potently distasteful at first that her later evolution into an essential element of team chemistry comes as a gradual surprise. With Harry, Ruth, Adam, Ros, Zaf, Jo, and Malcolm minding the store through much of seasons four and five, the series grows stronger and stronger.
Then in season six, everything gets turned up a notch. Without quite abandoning its crisis-of-the-week roots, the sixth year threads its weekly setpiece episodes together with a complex, season-long throughline involving a threat from Iran. Season six throws itself headlong into episode-to-episode continuity. Its more urgent timetables, more integrated storylines, and the earned goodwill of the roster all combine to take the show to another level. Its ten episodes are rife with compelling aspects: the mystery of Zaf’s disappearance, Adam’s reckless afair with an asset, Malcolm’s first field mission, Ros’ dangerous involvement with a sinister international organization, the gradual recruitment of a new agent named Ben Kaplan (Alex Lanipekun) and the return to the fold of an old one, Connie James (Gemma Jones) — all these elements integrate smoothly and seamlessly, and the results are brilliant.
Of course, having such a memorable peak year makes the subsequent ones suffer in comparison. The series begins a gradual decline in its last four years. When Adam Carter departs the show early in season seven, he’s just the first of many characters inadequately replaced, although Lucas North (Richard Armitage) is a good and interesting try. He starts well, and Armitage certainly has the chops for the role, but Lucas is a colder, darker presence, somewhat harder to invest in. As other characters leave the show and more pressure is placed on Norris and Armitage to carry the action, the series loses some of its warmth and continuity. The death knell for team chemistry comes early in season eight, when both Malcolm and Jo are written out. The newcomers slotted in to fill out the cast in seasons nine and ten are adequate performers, but not nearly as developed, and we never really get to know them. Nor do the season-long arcs of these later years hold up compared to the Iranian plot in season six.
That said, there are plenty of bright spots winding down the run. Excellent individual episodes are present right up into season ten, and if the casting changes seem more arbitrary and unplanned than usual, they continue to contribute story material. Season nine’s spark comes from newcomer Beth Bailey (Sophia Myles), a snarky operative from the private sector who reapplies to MI-5 to wash the blood off her hands. Beth is a promising new presence on the team who is unfortunately dispensed with offscreen at the end of one season. In season ten, a cocky new wiseguy tech shows up named Calum Reed (Geoffrey Streatfield), a character I appreciated more this time than during my first watch, when he felt like just another replacement. He’s hardly around long enough to explore, but he flavors the proceedings nicely with jerky sarcasm.
Even so, by season ten, familiar faces are hard to come by, and Section D’s grid feels like a ghost impression of its former self. Harry and Ruth are left to carry much of the emotional load in the final, six-episode arc, and they do an admirable job of it, in a modest wind-down that caps off the series and brings it some closure.
MI-5 is by no means a perfect series. It’s prone to melodrama and infodumps, and to generate tension it over-relies on shocking reveals, dark twists, and far too many mistakes from the team. But even as I saw its flaws more clearly, I came away from this rewatch loving the series more than ever. It’s an ambitious, intelligent, and challenging show, gutsy and stylish, well produced and chock full of memorable characters. It provides a singular blend of suspenseful action, creeping intrigue, thorny politics, and fraught workplace drama, and surely one of television’s best spy series.
