The Boer Wars were two wars fought in South Africa in the late 19th and early 20th centuries.
History
As the Sixth Doctor explained to Peri Brown, the Dutch Boers had settled in an area of South Africa called the Transvaal, which was rich in gold and diamonds. Hearing about this, many of the British flocked there to make their fortunes. Soon there were more British than Boers, but the Boers refused them any political rights. The British used this as an excuse to take over the Transvaal, including its gold and diamond mines. (PROSE: Players)
Queen Victoria was aware that there was going to be a second Boer War. (AUDIO: Fortitude)
References
The First Doctor claimed to have been present during the Siege of Mafeking. (TV: The Daleks' Master Plan, The Invasion of Time) Hugh Curbishley also mentioned Mafeking. (TV: The Unicorn and the Wasp)
The War Lords kidnapped soldiers from the Boer War for their War Games. The survivors were returned to Earth after the War Lords were defeated. (TV: The War Games)
In November 1899, the Sixth Doctor and Peri Brown rescued Winston Churchill when he was a war correspondent in the Boer Wars. (PROSE: Players)
Alexander Bruce fought with Mortimer Davey's father in the Boer War. (AUDIO: The Roof of the World)
Richard Lansing, a bureaucrat in the British Foreign Office who was assigned to Uzbekistan in 1919, was injured in the second Boer War. (AUDIO: The Memory Cheats) Arthur Daniels and William Spence both fought in the second Boer War. (AUDIO: Battle Scars)
Mr Rocastle, headmaster at the Farringham School for Boys, had fought in South Africa. Oliver Redfern had died at the Battle of Spion Kop. (TV: Human Nature) Private Tommy Watkins was also killed in the battle. (AUDIO: Tales from the Vault) George Rocastle and Alexander Shuttleworth's uncle likewise fought in the battle. (PROSE: Human Nature)
Lord Tamworth was involved in the Boer War. The Eighth Doctor claimed to have picked up some "colourful" Afrikaans during the war. (AUDIO: Storm Warning)
Alfred Talbot was killed in the war. (AUDIO: The Haunting of Malkin Place)