But from the moment Spooks debuted on BBC One, it was clear that this show was something different. By the time the genuinely shocking second episode had finished airing a week later - drawing hundreds of viewer complaints, but also much critical praise - the series had truly set out its stall.
Spooks: Originally broadcast from May 13, 2002 to October 23, 2011
Sticking to the template set out by these first two instalments, the Spooks of series one and two was a grounded spy thriller - each episode expertly straddled the line between escapist entertainment and often brutal realism.
Thanks to a combination of fantastic writing and solid performances, our central characters - Matthew Macfadyen's mercurial lead Tom Quinn, Keeley Hawes's glamorous but grounded Zoe Reynolds and David Oyelowo's eager-to-please Danny Hunter - all felt like real people, placed in real situations and real peril.
A succession of big-name guest stars also joined our regular team across the first two series - the likes of Buffy's Anthony Head, Star Trek: Deep Space Nine's Alexander Siddig and national treasure Hugh Laurie, who made two brief but fantastic cameos as sharp-tongued MI6 chief Jools Siviter before he was called away to play House.
But heading into its third series, Spooks struggled - the loss of lead trio Macfadyen, Hawes and Oyelowo left the spy series shaken and stirred and viewers were treated to such dubious delights as 2004's 'Celebrity' - which saw Lord of the Rings actor Andy Serkis awkwardly channel Kurt Cobain for 60 minutes.
But while Spooks was down, it was most certainly not out - once the shadow of Tom Quinn had receded a little, our new lead Adam Carter (Rupert Penry-Jones) began to blossom, heading down a dark and engaging path as the pressures of his MI5 career - and the loss of his beloved wife Fiona (Olga Sosnovska) - began to take a heavy psychological toll.
The fourth and fifth series saw the show back on a more solid footing: while the loss of one or more popular characters can sink a series, Spooks, like its closest US counterpart 24, managed to turn a negative into a positive. Audiences of five to six million remained hooked as old hands like Colin (Rory MacGregor) were written out in dramatic fashion and new favourites like iron-willed Ros Myers (Hermione Norris) stepped into the fray.
In addition to its frequent cast turnover, the show also stayed fresh by playing with format - taking another leaf out of 24's book, the sixth series of Spooks eschewed the usual case-of-the-week formula in favour of a single ongoing storyline that spanned all ten episodes. The change in format was a risk, but one that absolutely paid off, resulting in one of the show's best ever runs.
Though the single-story experiment was not repeated, Spooks continued to innovate in its seventh year. With Rupert Penry-Jones choosing to move on after four years, the show was faced with the prospect of replacing its leading man for a second time.
But rather than simply introduce another Tom or Adam copycat, the show's writers took a more interesting approach. While new cast addition Richard Armitage filled the void of ruggedly handsome male spy as the enigmatic Lucas North, later series of Spooks also focused more on the Grid team as a whole, and head of Section D Harry Pearce (Peter Firth) began to take on a more prominent role.
Originally more of a peripheral character, Sir Harry was absolutely crucial to the final few years of Spooks - his dark past, frequent moral dilemmas and sweet, unspoken love for Ruth Evershed (Nicola Walker) became the crux of the series.
When it came time to wrap the show up - with production company Kudos citing their desire to "kill it off in its prime" rather than see it become a relic - the writing team shifted focus firmly to Harry, Section D's last man standing. The final six-part series delved deeper into his personal life than ever before and, with the tragic death of Ruth, saw the veteran spymaster finally turn his back on the possibility of a 'normal' life in order to continue serving his country.
Ten series and nine years after it began, Spooks had come full-circle - though the show's focus and quality occasionally wavered, by the end it had returned to its roots and was once again telling stories about real people, real situations, real feelings.
It may have had an impressive visual flair and heart-in-your-mouth twists, but more impressive than any of that, the show proved that it was still possible to produce a glossy and entertaining drama without sacrificing character.
Any series that runs for nearly a decade will inevitably encounter a few hurdles along the way, but when it was at its best, Spooks truly was dynamite television.
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