With "A Good Man Goes to War" Steven Moffat managed to tie up several dangling story threads, fulfil an ambition to throw in an item of whimsical logic into Doctor Who (see below) and still leave audiences scratching their heads and begging for the next installment.

It is also the story in which Rory fully embraces the role of vengeful grown-up warrior (complete with Roman uniform) that has been his character arc since first appearing as a geeky young nurse in "The Eleventh Hour".

Here are a few things to keep an eye out for, the next time you watch:

(The episode is available on iTunes and Amazon.)

The original title of this episode was "Demons Run", although "His Darkest Hour" was also under consideration. And in Germany, it still is called "Demons Run".

Madame Vastra's first line is, "Thank you, Parker, I won't be needing you again tonight", and her driver replies, "Yes, m'lady". This exchange is a nod to Gerry Anderson's groundbreaking puppet TV series Thunderbirds, specifically Lady Penelope and her chauffeur Parker. It's also worth noting that the 2004 live action Thunderbirds movie starred two notable Whovians: Sophia Myles as Lady Penelope (Madame de Pompadour in "The Girl in the Fireplace") and Ron Cook as Parker (Mr Magpie in "The Idiot's Lantern").

https://www.youtube.com/watch?v=KiwZ8qeUZF0

Vastra later arrives at home, telling Jenny, "Send a telegram to Inspector Abberline of the yard. Jack the Ripper has claimed his last victim." Frederick Abberline was a real policeman, a Chief Inspector in the London Metropolitan force, and one of the leaders in the investigation of Jack the Ripper.

Strax was based upon a character from "Death to the Doctor", an unused script by Gareth Roberts from Season 5. He had created the idea of a disgraced Sontaran (that he called Strom) the disgruntled character of whom was deemed ripe for comic exploration.

There's a nod in the end credits for Russell T Davies as creator of the Judoon and Ood, but there are no Oods in this story. Actually, a scene had been written in which Ood Sigma helping the Doctor's Army in taking Demons Run, but it did not make it to broadcast.

https://www.youtube.com/watch?v=aKq0s0KUGbU

Similarly, Steven Moffat later said he had intended to include Captain Jack Harkness when the Doctor pulls his army together, but John Barrowman was too busy filming Torchwood: Miracle Day to take part.

Annabel Cleare plays Madame President Eleanor in the scene where we first come across Strax, the Sontaran nurse. Eleanor's son Arthur is played by Annabel's real-life son Henry Wood.

"A Good Man Goes to War" is the seventh episode of Season 6, and also the 777th episode of Doctor Who. However, as nobody spotted this until after the story was filmed, Steven Moffat missed the opportunity to put in any references to this fact.

https://www.youtube.com/watch?v=1e8tOF3PeH0

Steven Moffat first made reference to the idea that the Doctor could be the source of the human (meaning English) word doctor in a Usenet forum post from 1995, 10 full years before Doctor Who was relaunched. He said: "Here's a particularly stupid theory. If we take "The Doctor" to be the Doctor's name - even if it is in the form of a title no doubt meaning something deep and Gallifreyan - perhaps our earthly use of the word "doctor" meaning healer or wise man is a direct result of the Doctor's multiple interventions in our history as a healer and wise man. In other words, we got it from him. This is a very silly idea and I'm consequently rather proud of it."

Keeping up the firm tradition of hiring comedians as actors, this episode showcases Charlie Baker as the Fat One. Baker is best known to British comedy fans as a stand-up comic, who took part in the 2011 ballroom fundraiser Let's Dance for Comic Relief:

https://www.youtube.com/watch?v=ERnYETH3b1o

NEXT: 10 Things You May Not Know About ‘Let's Kill Hitler’

Now read the rest of the 10 Things You May Not Know About Doctor Who archive.