Roots: Rudyard Kipling's The Jungle Book (Mowgli, Hathi, Khan, Baloo, the wolf pack) and Kim (Kimball), while Lady Forster reads from Kipling's Tiger! Tiger! at the story's opening. A Passage to India (Adela takes her name from the book's Adela Quested and author E.M Forster, Aziz from Doctor Aziz, the Karabya caves may be based on the book's Marabar caves) The works of Edgar Rice Burroughs (the characters Edgar and Burroughs, but particularly the Tarzan series) Rider Haggard (Haggard's name) and R.K Narayan (Professor Narayan). Major Haggard refers to the works of H G Wells, Arthur Conan Doyle (The Lost World is also name checked) and Jules Verne, and quotes Wilde's "We're all in the gutter but some of us are looking up at the stars." The Doctor mentions captain Hook (Peter Pan), the Cheshire Cat (Alice in Wonderland) and quotes Newton's First Law of Motion and Julius Caesar Act IV (iii) ("There is a tide in the affairs of men...") and exclaims Oh, Calcutta! Tegan mentions Tigger from Winnie the Pooh, Pussy Galore from Goldfinger, the songs See You later, Alligator, Ten Green Bottles and Nellie the Elephant and Jungle Jim. Professor Narayan mentions Proust's Madeleine (from Remembrance of Time Past.) Lady Forster, a terrible paraphraser, adopts "The Doctor, I presume?" and John Dryden's Palamon and Arcite Bk 3 ("like pilgrims to the appointed place we tend..." - replacing Dryden's "inn" with "train") and Richard Lovelace's To Althea ("Iron bars do not a prison make" - instead of "Stone walls...") and Lady Caroline Lamb's description of Lord Byron ("Mad, bad and dangerous to nobody") and also quotes from Dante's Inferno ("Abandon hope all ye who enter here") and describes the jungle's 'Heart of Darkness' (presumably referencing the Joseph Conrad novella). Khan's snake is called naga, after a snake-deity featured in numerous Asian myth cycles. Crikey, that's a lot of Roots!

Goofs: Major Haggard refers to "Her Majesty's Railways" (in 1926 the British monarch was George V)

Can a balloon really catch up with a train? Would turning a balloon burner sideways really make it go faster?

Fluffs: In episode one Peter Davison pronounces Narayan's name as "Professor Naran"

Dialogue Triumphs: "Stubbornness is one of Australia's greatest exports"

Dialogue Disasters: "Me Tegan, you Djahn"

Continuity: Homogenite is a very rare, almost mythical monomolecular element forged in the heart of a collapsed star and ejected at the point of collapse. Because it is monomolecular, most instances are highly fragile and do not survive the initial stage. A peculiar aspect of homogenite is its tendency towards (in the Doctor's words) "Metamorphic metamorphosis", turning all it touches into stone or, more accurately, precious and semi-precious gemstones (Shardul Khan merges with the Emerald Tiger when he devour it, rendering him immobile.) It is more correctly capable of molecular synthesis - combining and reconstituting organic materials and even organic and crystalline material at the molecular level.

The Emerald Tiger crashed on Earth hundreds of thousands of years earlier, its impact crater forming the Karabya Valley. The crater was discovered in 1908 by Lady Adela and Lord Edgar Forster on an expedition to the Karabya Caves, which lead into the Valley below. After being infected with the blood of the Emerald Tiger, the girl Dawon was first turned into a weretiger and eventually a large tigress with emeralds for eyes and diamonds claws, and teeth strong enough to bite through metal (thugh a titanium chain can hold her.)

The TARDIS medical kit has drugs which will cure rabies.

Nyssa refers to Tegan as her best friend. She has heard of homogenite and its potential use as a cure for diseases such as Richter's Syndrome, but all research on Terminus was unable to source the substance and declared it mythical. She admits to still not understanding the rules of cricket [despite seeing the Doctor play it at Cranleigh Hall - see Links, as well as an entire season's worth in Stockbridge in Circular Time : Autumn] The metamorphic and restorative properties of homogenite restore her appearance and form to that of her younger (i.e. Terminus) self.

Tegan says her own mother was kindly (as opposed to her aunt - presumably Vanessa)

Turlough is a wearing a three piece suit and hat. He says that he always hated the works of Shakespeare

The Doctor has come to Calcutta to watch the second Unofficial Test match between All India and Marylebone Cricket Club (MCC), which the Doctor considers to be one of the best cricket matches of all time.

Location: Calcutta and Durgapur, on 31 December 1926 through to 1 January 1927.

Links: The Doctor discusses the Brigadier and Brendon School with Turlough (Mawdryn Undead). Tegan refers to Nyssa's husband Lasarti (Heroes of Sontar, Circular Time : Winter). Nyssa recalls the Doctor playing cricket at Cranleigh Hall (Black Orchid) and mentions Richter's Syndrome (Cobwebs) and Terminus Tegan recalls her Aunt Vanessa (Logopolis).

The Doctor invokes Sir Isaac Newton - "You've never let me down, Isaac" (Circular Time: Summer) and says "Brave heart, Adela."

The Bottom Line: "A walking embodiment of everything that's going to bring down the British Raj..."

...And another instalment of Alan Barnes' indefatigable efforts to incorporate wholesale the entire canon of English literature into Doctor Who. You're in safe hands with Barnaby Edwards, however, and the whole thing rushes by without too much fuss, with some great moments for the leads (Tegan in particular) and good guest spots as well. Recommended.