UNIT was an audio series produced by Big Finish Productions. It featured UNIT dealing with various problems, such as modern day terrorism, without the presence of the Doctor. A different series was launched in 2015 as UNIT: The New Series, focusing on Kate Stewart's UNIT.
In May2020, Big Finish released a special box set collecting all five stories from the series. In 2022, the UNIT series itself was relaunched in 2022 under the title of Brave New World, instead focusing on UNIT from the 1990s, headed by Brigadier Bambera and her team.
Unusually, the end of each episode of the first series closed with a next time trailer narrated by Nicholas Briggs. This would not become common practice until the new series began airing on television.
The series' cover art used an updated UNIT logo, a logo carried over to their first new series appearance in Aliens of London / World War Three.