Inspirations: Sleep No More

The episode title comes from Shakespeare - Macbeth Act 2 Scene 2: "Sleep No more / Macbeth does murder sleep".

Mark Gatiss had first thought about a story revolving around sleep in 2010, after suffering a bout of insomnia. The substance we call "sleep" - medically rheum - is a collection of organic material, including dust, skin, mucus and oil, which is produced by way of the eye cleansing itself overnight.

Gatiss was later shown an article about compressed sleep - becoming popular in the business world. Workers were reducing the amount of sleep they took to increase the number of hours they could use for work. The intention was to increase productivity but, of course, led to reduced efficiency through tiredness.

Gatiss thought of a future in which sleep could be artificially compressed so workers could be employed for all but a few minutes each day.

Knowing that Steven Moffat was looking to have more two-parters in Series 9, Gatiss' original idea was in this format, and included conflict between two factions - one which promoted this process and the other which argued for the natural way of things. They were known as the 'Wideys' - for Wide Awake - and the 'Rips' - for Rip Van Winkle.

Rip Van Winkle was the protagonist of an 1819 Washington Irving tale a Dutch-American who fell asleep for 20 years. He returns home to find his wife now dead, his daughter grown, and the old colonial America overtaken by the Revolution.

The process by which sleep was compressed would lead to the rapid growth of the creatures made from rheum, which Gatiss named Sandmen. The Sandman derives from German and Scandinavian folklore - a figure who sprinkles magical sand on the eyes of children to induce sleep and dreams. Rheum is a sign that you had been visited by him. Generally regarded as a benevolent character, ETA Hoffmann wrote a tale in which they were a more sinister figure (Der Sandmann, 1816).

The Doctor objects to Clara naming the creatures Sandmen, claiming "It's the Silurians all over again" - a reference to humans misnaming creatures.

The 1954 release of the song Mr Sandman by The Chordettes features in the episode as the jingle played by the Morpheus Pods. Morpheus was the Greek god of dreams, son of the sleep god Hypnos.

A working title for the episode was "The Arms of Morpheus".

This particular version of the song was originally going to feature as the alien "earworm" in an earlier Gatiss story - the one which eventually developed into The Idiot's Lantern.

Gatiss was happy to have a futuristic setting, as his earlier contributions to the series had tended to be historical in nature. The setting is a space station orbiting the planet Neptune. This had never featured in the series before, and its inclusion was inspired by a Horizon programme Gatiss had watched about the Voyager mission.

The station is named the Le Verrier. Urbain Le Verrier (1811 - 1877) was the French astronomer and mathematician who in 1846 correctly predicted the existence and location of Neptune purely through mathematics, explaining a discrepancy in the orbit of Uranus.

The role of Rassmussen was written specifically for Reece Shearsmith. He was one of The League of Gentlemen, along with Gatiss and Steve Pemberton, who had already appeared in Silence in the Library / Forest of the Dead. He had appeared briefly as Patrick Troughton in Gatiss' An Adventure in Space and Time in 2013.

In the episode, Japan and India have formed a new superpower following "The Great Catastrophe". Gatiss had recently visited both countries, and the latter is a reference to the 1984 story Frontios.

In terms of how the story is presented, as opposed to the plot, then this is Doctor Who's attempt at the "found-footage" style. This became all the rage, especially in the Horror genre, following the success of The Blair Witch Project. This 1999 movie was presented as though it were genuine camcorder footage from a party of three film school students making a documentary about the Blair Witch. They travel to rural Maryland in search of the story, learning of a local 1941 serial killer on their travels.

The entire film consists of their raw documentary recordings, supposedly found after they vanished in the area.

The style became hugely popular with low budget film-makers, though a big sci-fi blockbuster also employed it - JJ Abrams' Cloverfield (2008), directed by Matt Reeves. This depicted the attack on New York by a massive monster (plus some smaller creatures in the subway tunnels).

The problem with the style is that it became overused - especially by those cheap productions. The other problem is how unrealistic they are, despite the whole point being that they're supposed to look as if they are genuine recordings. People running for their lives simply would not keep filming monsters or zombies snapping at their heels.

By the time this story came along the style had fallen out of fashion, replaced by the more static CCTV / home security camera set-up, as seen in the Paranormal Activity franchise.

The ending is odd for Doctor Who at this time, with the Doctor never actually neutralising the threat. This had happened in the programme in some of the historical stories of its earlier days, when the Doctor and companions simply fled the setting in the TARDIS, leaving events to unfold and with some villains undefeated (most notably Tlotoxl in The Aztecs).

Things were left open-ended here purely because a sequel was planned. However, the episode proved unpopular and Moffat was planning his exit from the series anyway - and Gatiss intended to step away from it with him. He wrote Empress of Mars instead - a story he wanted to write whilst he still had the chance.

Next time: The Doctor gets caught in a trap within a Trap, and Clara gets the bird...