Great Britain
Great Britain was one of the British Isles.
Correcting Mr Copper's use of "Great France" and "Great Germany", the Tenth Doctor clarified that "only Britain [was] great". (TV: Voyage of the Damned)
Geography
Its capital city was London, with Edinburgh and Cardiff serving as the regional capitals of Scotland and Wales respectively. (TV: The War Machines, The Highlanders, The Unquiet Dead) Britain shared its eastern coast with the North Sea. (TV: The Lie of the Land)
Nationality
The Doctor's long association with the country led them to often be identified as British, typically when they were visiting other parts of Earth. (TV: The Gunfighters, Doctor Who, Demons of the Punjab)
Influence on the Doctor
The Doctor visited Great Britain more than anywhere else on their travels. He developed a great affinity for it and even lived there for some time. (TV: "An Unearthly Child", et al.) The Doctor was well acquainted with the island's historical figures, and was a friend, an antagonist, and even a lover to several of her monarchs. (TV: Voyage of the Damned, The Crusade, Tooth and Claw, The Impossible Astronaut, The Day of the Doctor, The Shakespeare Code, The Beast Below) In 1562, when the Tenth Doctor married Queen Elizabeth I, he was effectively King of England. (TV: The Day of the Doctor) The Doctor sometimes considered themselves to be British and would often refer to themselves as such, (TV: Doctor Who, PROSE: History 101, et al.) though on one occasion the Tenth Doctor said he wasn't English. (TV: The Day of the Doctor) He accepted a British knighthood from Queen Victoria, (TV: Tooth and Claw) and, in his fifth incarnation, an English knighthood from an imposter posing as King John. (TV: The King's Demons)
History
Early history
After several failed attempts, the Roman Empire succeeded in conquering Britain in 43. The Roman occupation of the island lasted until the early 5th century. (AUDIO: The Wrath of the Iceni) One of these failed attempts was led by Julius Caesar in 55 BC. (AUDIO: Living History)
In 305, the Eighth Doctor and Charley Pollard stopped the Nimon from invading a Roman fort in Britannia. (AUDIO: Seasons of Fear)
The United Kingdom
In 1879, Victoria was Queen of the "United Kingdom of Great Britain and Ireland." (TV: Tooth and Claw) That year, she established the Torchwood Institute to defend the realm of Great Britain by investigating "the unusual, the strange and the alien". (TV: The New World)
By the 21st century, Britain was identified as one of the most obese nations of the galaxy. (TV: Partners in Crime)
In the Year That Never Was where the Toclafane ruled Earth, the Saxon Master's new name for Britain was Zone One. (TV: Last of the Time Lords)
In the 24th century, it was known as ConCorp. (AUDIO: Antidote to Oblivion)
By the 26th century, it was known as Greater Britannica. (AUDIO: Scorpius)
In the 29th century, due to solar flares, the United Kingdom abandoned Earth for Starship UK; Scotland opted for its own starship separate from the rest of the kingdom. (TV: The Beast Below) This continued until at least the 52nd century. (TV: The Pandorica Opens)
During the Ice Age of 5000, Brittanicus Base was located in Britain. (TV: The Ice Warriors)
