Roots: The Doctor likens Mondas to [Britain during] 'the 1950s', but the setting is informed also by Britain during the Second World War with ration books, a state of siege, 'calling up' for service, and trams. Holocaust concentration camp anecdotes (stripping of prisoners followed by 'medical examinations' which turn out to be something more). The Church of the Latter Day Saints (Mondas' church of Former Day Souls). The Doctor quotes Thomas Shadwell ('the way of all flesh'), evokes Francis Barraud's most celebrated painting ('You see, Zheng? Your Master's Voice') and refers to the Committee as Solomon. Frank paraphrases the song 'Love Potion No. 9' ('Full charge no. 9'). Battle from Beyond the Stars (the last movie to play in the cinema).

Technobabble: There is an isolator fail-safe in the TARDIS. Doctorman Allan uses a corporeal scanner.

Double Entendres: 'Mister Dodd, don't say you don't know a back route'

Dialogue Triumphs: 'He can barely manage a rictus grin. That's the trouble with plastic surgery.'

'I am superior to you. Be proud while you still have the capacity.'

'How did this start? Just a few hip replacements and breast implants - vanity's a killer, isn't it?'

'We live in a pit, Constant. The dark times are getting darker'.

Continuity: Mondas' society as observed by the Doctor and Nyssa resembles that of the United Kingdom in the 1950s, set in enormous subterranean caverns beneath an artificial biosphere above the planet's upper surface (there is no weather, although older members of the population remember it). People of different colour are evident (Dodd offers limbs in 'all colours, shapes and sizes'), and identity papers are required for every individual. Titles of tradespeople and professionals on Mondas include Crewman, Doctorman, Sisterman and Electroman. Public transport is usually via tram, although augmented horses still exist. Football, greyhound racing (Dodd likens the Doctor to one), television, radio, coin operated telephones (with manned switchboards) and cinema exist (one movie is 'Battle from Above the Sky!'), although cinema houses have since been closed. Tea remains, and Doctorman Allan hoards wine from the old Mondas.

The city home of the remaining Mondasians is separated into sectors named after compass points (Nyssa claims to come from the South sector), its population living in apartments and numbering just under three thousand. Streets are numbered rather than named. Features identified include a church and graveyard, hydroponic factories (growing among other things beetroot and turnips), and to the north, 'stalag stacks', likely connected to the geothermal energy supply feeding the city and its leaders. Power is conducted throughout the city in cabling located underneath paving stones (and usually sought after by rogue cybermats). Despite this, there is a curfew after eight pm (Mondas would appear to work on the same clock as we do, including measuring time in days, hours and minutes), and patrols check energy use. Some animals continue to exist under domestication, including the horse (bionically enhanced), and caged bird (Yvonne Hartley's is a 'Trillerby Mk II - an older model). Despite such augmentation these creatures are considered as 'real' as an augmented human - no distinction is yet made. Schooling also continues - Frank Hartley studies logic and cybernetics.

The hemispheric location of the city is not identified, but the apparent equivalent of Christmas occurs during winter. During this 'holiday' household trees are decked with adornments which in turn symbolise the forests of the past (the tree), the stars in the sky above them (lights), the worlds through which they pass (baubles), their path through space (the trail of tinsel), and the sun they once orbited (the uppermost star). Religion barely exists as (probably) a form of ancestor worship (via the Church of Former Day Souls), and pseudo religious orders still exist in the case of Sisterman Constant, who mentions 'heaven' and gives processing candidates (many selected by herself) blessings. One of their vows is of abstinence.

The Cherrybowl Nebula is 'a crucible of unstable energy'; space farers avoid it like the plague. Mondas knows of Earth (but doesn't name it) as its twin orbiting the Sun directly opposite Mondas. When the Moon 'exploded' from Earth to become its satellite, Mondas was thrown out of its orbit due to the imbalance. At the story's conclusion (and before the Doctor and Nyssa leave), Mondas begins its return journey to the Solar system, aided by propulsion units.

Disease on Mondas is common due to poor living conditions; tuberculosis is among identifiable ailments (every member of the Hartley family is ill or on medication of some form). Bionic limbs are commonplace, including 'heartboxes' for cardiovascular ailments. In competition for artificial limbs is a near black market in 'second hand' human limbs, often stored either in vacuum packs or in freezers. The dead are sold to dealers for this purpose. Despite this artificial limb and organ replacement seems to be most popular, incorporating titanium and plastic augmentation. According to Dodd the noise from excessive augmentation can drive the individual 'crazy', promoting them to voluntarily have their emotions surgically removed [perhaps via a form of prefrontal lobotomy?]. Policemen appear to be the only members of the surface community with outwardly visible cybernetic parts, although they have no faceplate and are recognisably human with synthesised voiceboxes. Maintenance of the surface biosphere is carried out by 'fully suited' workers - Cybermen in all but name, due to the hostile conditions there (guaranteeing only a nineteen percent survival rate). Crewman Donald Philpott was the first man to walk on the surface. Travel to the surface of Mondas is via burrowing capsule (also an unreliable means of travel - Zheng's capsule fails and crashes). Originally a force built up of volunteers, 'call-ups' are common when one reaches suitable age - ultimately and inevitably the entire population is 'processed' (the term used for cyberisation in this story) beyond the conclusion. They do not react adversely to gold, but are still at a vulnerable stage. Frank remarks that the processed Yvonne's hands are cold. Cybermen are of uniform height and are programmed during processing (an override switch on their person terminates the procedure and the patient) - their first priority is to protect the Committee. Augmentations identified include pulmonary units and 'logic walls'.

It is not explained what function cybermats fill chiefly, although the Committee uses them for surveillance. Domestic 'mats' routinely break free of their programming, occasionally swarming or 'nesting' outside, necessitating 'Mat catchers' who use 'cheesers' - power generators to lure them out into the open and trap them. Other models of 'mat' include the Deluxe Mark VI (available in chrome finish), and the Committee's Mark XII surveillance model, in black. Cybermats can apparently sense a power source from a mile away.

At the head of Mondasian society and dwelling within a fortress-like palace is the unseen Committee, a bionic gestalt of twenty individuals joined (as the Doctor sees it) like a hydra, with enlarged heads and withering malnourished bodies. The Committee superceded the former decadent government, but by the conclusion of the story they have become the first Cyberplanner. Nyssa remembers the Autumn festival on Traken, when the leaves turn to amber. During this paper lanterns are hung in the trees, singing occurs at the garden gates and panniers of red and purple fruit are presented with which the commoners and consuls pelt each other in a ceremonial battle. Nyssa thinks 'the pictures' means a kind of art gallery.

The Doctor carries Chinese crackers and matches in his pockets. An isolated lobe at the base of a Time Lord's brain deals with their bodily and motor functions, allowing other parts of the brain to optimise all calculation and data assessment. After being scanned, aspects of the Doctor's physiology are incorporated into Cyber processing schematics.

Location: Mondas, near the Cherrybowl Nebula, at the farthest point of its retreat from the Solar System.

Q.v.: 'Cyber History'

Untelevised Adventures: The Doctor has been saving a gift of tea from the Nipponese Emperor Tokugawa Ieyasu for a special occasion [presumably this took place sometime between Ieyasu's being accorded the title of shogun 1603 and his death in 1616].

Links: 'The Tenth Planet' (for obvious reasons, but there is also the suggestion of a link with the name of one of its Cybermen, Krail, in the family name Krailford, and perhaps in Krang via Frank's friends the Chang twins), 'The Tomb of the Cybermen' (logic at the forefront of Cyber culture), 'Revenge of the Cybermen' (gold as a potential threat to Cybermen), 'The Keeper of Traken', 'Earthshock' (Adric's death), 'Attack of the Cybermen' (Mondas' propulsion unit)

The Bottom Line: 'We all want immortality, don't we? But with a chrome finish?'

With the use of English twentieth century history as its cultural touchstone, never has the oft-quoted Cyber-description 'they were like us once' been more apt. 'Spare Parts' is a tour de force, repulsive, heart breaking and thrilling in turn; quite easily the best Cyberman story of the series. Moreover, the pairing of the fifth Doctor and Nyssa couldn't have been better managed, or more appropriately chosen.