From the Doctor to Des, David Tennant never stops surprising with his magnificent range

Nilsen's quietly sinister nature is portrayed effortlessly by Tennant from the minute we meet the killer, who immediately confesses to the horrific murders he's committed. However it's not until later in the first episode – during Nilsen's interview with police detective Peter Jay (played magnificently by Daniel Mays) – that we see the actor's performance in its full, blood-curdling glory.

Tennant's nonchalant, dead-eyed delivery of Nilsen's crimes to the gobsmacked police officers listening in shock makes for one of the most intense scenes in television this year, and for those watching his portrayal, it's easy to forget that this is the same actor who charmed the nation and won the hearts of a generation of teenage girls (myself included) as The Doctor.

While Tennant's incredible range shouldn't come as a surprise to viewers at this point in his career, Des is the latest demonstration of his chameleon-like ability to transform into a widely contrasting cast of characters – from benevolent aliens and mischievous demons, to chilling serial killers and complex modern-day men.

Like many, I was first introduced to David Tennant when he was cast as the Tenth Doctor, following Christopher Eccleston's departure from the BBC's Doctor Who reboot in 2005. While he was left with big shoes to fill, Tennant slipped effortlessly into the converse trainers that became a staple of his Time Lord's outfit, with his infectiously exuberant delivery, elastic facial expressions, cheeky grin and complex yet compelling speeches.

His multi-layered performance as the Doctor could instil both fear and laughter within the show's wide-ranging audience, while few could hold back tears during some of the Time Lord's most heartbreaking moments (I'm still not over his farewell to Rose on Bad Wolf Bay). Not to mention Tennant's hugely convincing English accent, which teenage me was shocked to discover was fake after hearing the actor's natural Scottish tones during an interview.

If his ability to jump from emotional extremes at the drop of a hat wasn't obvious during his five year tenure as the Doctor, his subsequent career laboured the point more so. Having already made a brief, yet scene-stealing appearance as the unhinged death eater Barty Crouch Jr in Harry Potter and the Goblet of Fire, he later starred as haunted detective DI Alec Hardy in ITV's Broadchurch, highlighting his charismatic on-screen dynamic with the award-winning Olivia Coleman which attracted critical acclaim for both actors.

Tennant continued to branch out into sci-fi and the supernatural, taking on the roles of maleficent mind-controlling villain Kilgrave in Marvel's Jessica Jones and Earth-dwelling demon Crowley in Good Omens, whilst flexing his comedic muscles in lockdown sitcom Staged (in which he played an exaggerated version of himself), W1A and comedy-drama There She Goes.

The 49-year-old actor has taken on characters from both ends of the moral spectrum and has played killers before, with his turn as Dr Edgar Fallon in Netflix's intense drama Criminal and secretly-menacing husband Tom in Deadwater Fell earlier this year – but his performance in Des is on a whole new level.

Not only does the award-winning actor look eerily similar to the killer in the ITV drama, Tennant's portrayal of the manipulative yet seemingly unassuming monster, with his calm and collected explanation of the murders he committed and his own rationalised thoughts as to why he may have done what he did, is truly terrifying.

While the miniseries, which comes to a conclusion tonight, has been a gripping and enlightening watch, highlighting the irreversible damage caused by a murderer who managed to stay undetected for years, it has also created a role of a lifetime for Tennant, who has once again proven his talent for playing the epitomes of both pure goodness and unadulterated evil.

Des concludes tonight at 9pm on ITV. Find out what else to watch with our TV Guide.