In August 2011, Kudos Film and Television, the production company behind Spooks, announced that the tenth series will be its last, as they wanted the show to end "in its prime".

In this series, former Russian spy-turned-politician Ilya Gavrik (Jonathan Hyde), Harry Pearce's (Peter Firth) opposite during the Cold War, proposes a strategic partnership between Russia and the United Kingdom.

As well as Firth, Nicola Walker, Max Brown, Shazad Latif, Simon Russell Beale, Lara Pulver and Geoffrey Streatfeild are included as the main cast.

Reviews of the final series were polarised between positive and negative, with critical opinions ranging from "as impressive as ever" to looking "tattered and tired".

The tenth series began with Harry on "gardening leave" after trading Albany, a state secret, for Ruth's safety.

"[5] Shazad Latif also reprised his role as Tariq Masood for the first two episodes, and Simon Russell Beale returned as Home Secretary William Towers.

Pulver described Erin as "young", "feisty", and has got "something to prove... but she has a maturity and a delicacy with the matters she's handling that makes her really good at her job".

[17] The storyline also features Harry and the Section D team forging new relationships with different countries, including Russia, which in the series has a better image in the Middle East.

[18] Episodes of the tenth series made references to such world events in 2011 such as the 2011 Libyan civil war,[2] and the death of Osama bin Laden.

Executive producer Jane Featherstone decided to end the series during its writing stage, stating "It's very tempting to keep going, and we have had ongoing conversations with our partners at the BBC about it, but the heart of the show has become those two characters [Harry and Ruth] and I feel they own it.

[16] Writers Brackley and Vincent noted "there was always a strong possibility of it being the end, so throughout the [writing] process we were looking for ways to infuse it with a sense of finality.

"[17] Firth believed the series was getting to a point where the producers were starting to run out of story ideas, as virtually every type of antagonist has been featured.

[20] In early September a short teaser trailer was released, which includes clips of the series with the tagline "This is the end.

[27] However, despite being trounced by Downton Abbey, Spooks saw a gradual increase in viewership over the subsequent weeks,[28][29][30] leading up to a boost of up to 5.13 million viewers for the final episode on 23 October 2011.

Among the positive reviews, Peter Sharples of CultBox rated the series five out of five, commending it for looking "more cinematic than in previous years", adding "any reduction in budget certainly doesn't show, with the action scenes as impressive as ever".

Sharples was also appreciative of the "pretty strong" new cast, including Pulver for "making a big impression as a tough action girl juggling responsibilities as section head with those of a single parent", and Streatfeild for being "amusingly cocky and insubordinate".

He suggested that "Lara Pulver never seemed comfortable as Erin Watts, Section D's new head, because she looked as if she'd been seconded from a modelling agency, while promoting Dimitri …merely allowed him to become more faceless by the hour".

[35] Andrew Pettie of The Daily Telegraph believed that Spooks is looking "tattered and tired", with a plot that is "about as up-to-date as the Berlin Wall".

But in recent years the most enjoyable bits of Spooks have also been the least plausible, as the scriptwriters really let their hair down and do something silly", he rated the premiere episode two out of five.

[36] Tom Sutcliff of The Independent also rated the premiere episode two out of five, stating "Spooks isn't even true to its own account of the world, let alone the one the rest of us inhabit.

At the next, one of Harry's boys was sauntering past the boot of his car to clip on a tracker, in full view of the target and his security men".