UN's legal actions against the UNIT acronym

In 2005, the real world United Nations took legal action against the naming of the ficticious United Nations Intelligence Taskforce, which had been depicted as such in Doctor Who media since 1968's The Invasion. This resulted in the fictional organisation being renamed to the Unified Intelligence Taskforce (initially UNified) beginning with the 2008 television story The Sontaran Stratagem.

Despite this, many Doctor Who stories have still used the original acronym during stories set in UNIT's past.

Legal actions
The issues began in 2005 with the second-released Doctor Who tie-in website, U.N.I.T., which was styled to look like an authentic, in-universe website; by conveying this illusion so effectively, the website had very little indication of its fictionality. That being said, the website had a disclaimer page, although this too was styled to look in-universe, barring a small section at the very bottom which broke this illusion. It also had a direct link to the real world United Nations website.

Despite this disclaimer, after the launch of the website, the real United Nations began to take legal action. They first faxed BBC lawyers, requesting the name to be changed, but the lawyers misinterpreted this as a hoax and displayed the fax in a kitchen in pride. Their pride soon turned to panic when the UN threatened imprisonment under the Geneva Convention, and the main website editor at the time, James Goss, was alterted to the UN's actions and emailed Russell T Davies, fearing extradition. Script editor Helen Raynor quickly came up with the new name, the "UNified Intelligence Taskforce", and the disclaimer on the site was made more prominent at the behest of the UN. Thus, this was the catalyst for the name "United Nations Intelligence Taskforce" being changed to the "Unified Intelligence Taskforce" in all later appearances.

On 13 November 2022, as part of a discussion about the incident on Twitter, Goss retrieved the first fax from an old hard drive. However, the second fax that included the legal threat was lost.