Black market
A black market was a covert or illegal market or trade operation outside of 'normal' business or retail operations. (AUDIO: Nocturne [+]Loading...["Nocturne (audio story)"]) They were run by or through criminal organisations. (PROSE: Dragons' Wrath [+]Loading...["Dragons' Wrath (novel)"])
In 1979 response to Wilkin's assertion that Professor Chronotis' rooms had been "stolen" the Constable wryly commented that there wasn't a "black market in rooms". (TV: Shada [+]Loading...["Shada (TV story)"])
The Order of the Custodians found that MDZ Research had been buying up any non-terrestrial weaponry on the black market. This included a Dalek gunstick which was recovered by a reconnaisance scout on 1 January 2019. (TV: Resolution)
There was a black market selling alien species on Earth in the 21st century. John Harrison paid millions for a group of Skullion slaves who had crash landed in Central Asia. They were brought across Europe and then across the English Channel. (TV: The Man Who Never Was)
Bloorm Vungah Bart Slitheen, Dax Fex Fize Slitheen and Korst Gogg Thek Lutiven-Day Slitheen were planning to sell Luke Smith's telekinetic energy on the Energies Black Market on Antara IV, but couldn't fulfil their plans because Luke escaped. (PROSE: The Lost Boy)
Nardole remarked that he would start a black market if there was more than three people in the room. (TV: The Doctor Falls)
In Pete's World, Jackie Tyler claimed that here birthday parties hosted "plenty of black market whisky". (TV: Rise of the Cybermen)