Steven Moffat regenerated Doctor Who with a virtual double defibrillator to the chest. Well, the Doctor does have two hearts. But not only did Moffat introduce batty new Doctor Matt Smith to the series in an ambitious episode which heralded a new dynamic, he also retooled the tone of the series.

With Moffat in the driving seat as showrunner, the series, which had been revived in 2005 by lifelong Doctor Who fan Russell T. Davies and brought up to date, suddenly felt even more contemporary.

Taking over in 2010 for Series 5, Moffat’s tenure, in particular, made the show feel a world away from its origins – it first hit screens in 1963. And yet at the same time it was, and still is, respectful of its legacy. For a start, it’s always had the same theme tune, but with Moffat’s turn in the hot seat, we got a brand new reworking of the theme music, logo and opening credits, announcing his arrival with a fanfare.

The upcoming tenth series marks Moffat’s last in charge. We’re guessing it will also be his final involvement with the show full stop. He worked on it as a writer across all four Russell T. Davies-helmed series before eventually stepping up. With that in mind, we look back on five brilliant things Moffat did for the show.

1. The oldest Doctor ever took over from the youngest


Matt Smith is the youngest actor ever to portray the Doctor in the series. He was 27 when he first appeared in the role, departing three years later. And while William Hartnell was the oldest at 55 at the start of his reign, bowing out at the age of 58, Peter Capaldi was just a few months younger when he first picked up the sonic screwdriver.

Capaldi, however, turns 59 on April 14, making him arguably the oldest Doctor. In the main series, at least, and as far as consecutively recurring incarnations go. William Hartnell did reprise the role for the 10th anniversary special in the 1970s, while John Hurt was 73 when he appeared as the War Doctor in the special 50th anniversary episode in 2013.

2. The 50th anniversary episode


This landmark special episode of Doctor Who was called “The Day of the Doctor” and brought together three different versions of the Doctor – Matt Smith’s 11th Doctor, David Tennant’s 10th and John Hurt’s War Doctor.

The episode was written by Moffat, who wanted to create an incarnation of the Doctor with more gravitas for a story which centred around the Doctor himself, rather than the people he usually flies in to help. The main event was the Time War, with the plot revolving around the pushing of the button that sets off a weapon of mass destruction.

Moffat wrote the role of the War Doctor as an incarnation that was “much deadlier and more serious” than other Doctors, and who could conceivably have “done something terrible”.

3.That double-whammy overhaul of lead characters


For the first time since the series was rejuvenated in 2005, we got a concurrent re-casting of both Doctor and companion at the beginning of Series 5 and Moffat’s tenure. It made a huge impact. Suddenly, there were two brand new main characters to get to know five series in. And both came with bags of personality.

Matt Smith’s Doctor makes a startling first impression, crash landing the TARDIS into a garden shed then descending on the home of a young girl who’s home alone. He proceeds to demand she make him food, then throws away or spits out everything this young version of Amelia Pond gives him.

Amy Pond’s entrance into the series is similarly impactful. After first meeting Amelia as a child, we later see her as a grown woman played by Karen Gillan – dressed as a police officer and declaring herself a stripper.

4. The introduction of Doctor Who’s first openly gay companion


In Series 10’s Bill Potts, Moffat has overseen the casting of Pearl Mackie in the role of the Doctor’s latest companion – who happens to be gay. While it’s true to say that there have been gay characters in the series before now, this is the first primary companion of the Doctor’s to be open about her sexuality. And, crucially, it’s not even really a thing for her – or Mackie who has stated that it’s not a defining characteristic of Bill. Which is exactly as it should be. Yay 2017!

5. The Silence

Doctor Who
These guys are funny looking

A scary alien race with a scary name, these fellas take humanoid form but have really creepy faces with big skull-like eye cavities, little nostrils and no immediately obvious mouth. They’re a religious order, and Moffat designed them to be scarier than any previous Who villains. They join the ranks of the Cybermen and Daleks as recurring bad guys. First seen in the opening episode of Series 6, their existence is little known because once seen, they’re immediately forgotten after looking away. However, suggestions they make live on in the consciousness which makes them extremely dangerous.

We’re looking forward to a whole series more of Steven Moffat-steered science-fantasy action once the new series kicks into gear on April 15, before both Moffat and incumbent Doctor Peter Capaldi bow out. The show will usher in a new era next year, as replacement showrunner Chris Chibnall comes aboard for Series 11 – bringing with him a new Doctor.

Kim Taylor-Foster
Kim Taylor-Foster is Entertainment Editor for Fandom in the UK. She was raised on an unsteady diet of video nasties and violent action flicks.