ID cards (PROSE: Operation London [+]BBC webteam, U.N.I.T. (BBC, 2005)., Silver-Tongued Liars [+]James Wylder, Cyberon (Arcbeatle Press, 2020)., A Worthy Successor [+]James Hornby and James Wylder, Cyberon (Arcbeatle Press, 2020)., etc.) also known as identity cards (PROSE: Top Secret [+]The Dalek Outer Space Book (Dalek annuals, 1966).) were a form of identification.
UNIT's ID cards were known as UNIT IDs. (AUDIO: The Blue Tooth [+]Nigel Fairs, The Companion Chronicles (Big Finish Productions, 2007).) There also existed "UNIT passes". (GAME: Lost in Time [+]Doctor Who video games (Eastside Games, 2022).)
Fake IDs were available. (TV: The Long Game [+]Russell T Davies, Doctor Who series 1 (BBC One, 2005)., PROSE: The Party in Room Four [+]Simon Guerrier, The Panda Book of Horror (2009).)
History
Alien experts from UNIT and other groups wore ID cards which were electrified by Jocrassa Fel-Fotch Passameer-Day Slitheen. Though the electricity was deadly to humans, the Ninth Doctor, being a Gallifreyan, survived and attached his ID card to a Slitheen, resulting in the pain being shared amongst the family. (TV: World War Three [+]Russell T Davies, Doctor Who series 1 (BBC One, 2005)., Revenge of the Slitheen [+]Gareth Roberts, The Sarah Jane Adventures series 1 (BBC One and CBBC, 2007).) Just prior to this, Staff Sergeant Annie Frederick remarked on how quickly Number Ten had created the Ninth Doctor's pass. (PROSE: Operation London [+]BBC webteam, U.N.I.T. (BBC, 2005).)
By the time Martha Jones was training at Royal Hope Hospital in 2008, (TV: Smith and Jones [+]Russell T Davies, Doctor Who series 3 (BBC One, 2007).) Martha had an ID card. According to one account, her ID card stated that her Authority was "RH0495" that her Number was 0/39. (PROSE: ID Cards [+]Doctor Who online fiction (BBC, 2007).) An alternative account instead stated that her Authority was "RH0776" and that her Number was 0/75. (PROSE: "Planet Earth" [+]Part of The Time Lord Letters, Justin Richards, BBC Books (2015).) A blank Royal Hope Hospital ID had a barcode which read "VOTE SAXON 2306801B" when decoded. (PROSE: ID Cards [+]Doctor Who online fiction (BBC, 2007).)
P.R.O.B.E. operatives carried ID cards: Louise Bayliss showed hers to Brittany Mordley in 2008, (PROSE: Silver-Tongued Liars [+]James Wylder, Cyberon (Arcbeatle Press, 2020).) and Giles and Archie MacTavish showed theirs to the security guard of the Vault, Donovan, in 2011. (PROSE: A Worthy Successor [+]James Hornby and James Wylder, Cyberon (Arcbeatle Press, 2020).)