The TARDISGenerally, TARDIS is written in all upper case letters, but many examples of the form Tardis are found in media and, occasionally, licensed publications. In the 2005 series episode World War Three, the caller ID of the TARDIS is displayed on Rose Tyler's mobile phone as "Tardis calling." This usage is consistent with current British press style, in which acronyms are referred to with only the first letter capitalised (for example, Nato), while initialisms (which are not pronounced as words), such as BBC, are capitalised in their entirety.