Brigadier Alistair Gordon Lethbridge-Stewart
c.1968 – 1976
Lethbridge-Stewart was the first Commanding Officer of the UK Branch of UNIT having being appointed to this position when the organisation was founded.
We do not know what date UNIT was founded due to the UNIT Dating Controversy, but 1968 was the year “The Invasion” first aired, which was UNIT’s first onscreen appearance. Lethbridge-Stewart retired as CO in 1976, as stated in “Mawdryn Undead”. However, he continued to be called back into service by UNIT on a number of subsequent occasions.
1976 – c.1980
Colonel Faraday appears in “The Android Invasion”. Though not explicitly stated in the show, I would argue that it was Faraday who took over command of UNIT when Lethbridge-Stewart retired (for my reasons why I believe Faraday to be UNIT's CO, see my entry on The Sporadic Years).
We do not know when Farady left UNIT, but according to the audio drama “The Oseiden Adventure”, he is still with the organisation in 1979.
Colonel Charles Crichton
c.1980 – Late 1980s
All we know about Crichton is that he was Commanding Officer of the UK branch of UNIT in 1983.
In the show, Colonel Crichton is listed as being Lethbridge-Stewart’s replacement. However, this is a throwaway line in “The Five Doctors”, and it is not explicitly stated that Crichton is his immediate replacement. If he was indeed the immediate successor of Lethbridge-Stewart, then by the time of “The Five Doctors” he has been UNIT’s CO for seven years. According to the novelisation of Downtime, he was still UNIT’s CO in 1995, having been promoted to Brigadier. This means that he has been UNIT’s CO for almost 20 years, which is a ridiculous assertion. Military postings just don’t last that long (not to mention the fact that his appearance in the Downtime novelisation is contradicted by the UNIT Dominion audio dramas, and I always give precedence to the audios over the novels since they contain the real cast members. In addition to that, the Downtime novelisation has Bambera as a Captain, meaning that within two years she will be promoted to Brigadier to replace Crichton. A promotion from Captain to Brigadier, missing out the intervening ranks of Major, Lieutenant Colonel and Colonel, in less than two years is preposterous! It was clearly written by someone who has no idea how the military really works (which is an accusation that can be levelled more and more at Doctor Who these days!!) and resultantly I don’t hold that novelisation in very high regard. Thankfully, neither Crichton nor Bambera were in the video version of Downtime, which is the version I count as the ‘real’ one).
Colonel Lafayette appears in the “UNIT Dominion” audio dramas, in which he is stated to have been in charge of the UK contingent of UNIT for “three months”.
"UNIT Dominion" does not give a setting, but we can reasonably assume that it is in the late 1980s (for a start, Dr Klein, UNIT’s Scientific Adviser, records things onto cassette tapes rather than CDs). Additionally, the Doctor meets Dr Klein again in a later adventure (“Persuasion”), which is set in 1990, so we know that Dominion comes before then chronologically.
Major Wyland-Jones replaces Colonel Lafayette when the latter is killed in “UNIT Dominion”.
As a Major, Wyland-Jones is the lowest ranked Commanding Officer we’ve yet seen. The story tells us that Geneva had been grooming to him to replace Lafayette for “weeks”, but that doesn’t explain why they would be preparing an officer of that grade, when all the previous Commanding Officers have been substantive Colonels or above. One wonders if he was promoted shortly after this adventure (to Lieutenant Colonel?). Perhaps UNIT cutbacks meant that they were trying to save money on higher salaries.
Brigadier Winifred Bambera
c.1990s – early 2000s
We see Brigadier Bambera as Commanding Officer of UNIT UK in “Battlefield”, set in 1997. We are given no indication of how long she has been in charge. She is one of only two Brigadiers to command the UK branch, as all other COs hold the rank of Colonel. It is entirely reasonable to suggest that there was at least one other Commanding Officer of UNIT who served between Wyland-Jones and Bambera, whose post would cover the period of the early to mid-1990s.
Colonel Ross Brimmicombe-Wood
Early 2000s – Early 2005
Colonel Brimmicombe-Wood is the CO of UNIT UK in the first series of UNIT audio dramas (though it turns out he was a traitor and working for ICIS all along).
Colonel Robert Dalton
Colonel Dalton was brought in as Acting Commanding Officer when Brimmicombe-Wood was kidnapped. He only held the post for a month or so before being killed by a bomb blast in Downing Street.
Colonel Emily Chaudhry
2005 – c.2007
Colonel Chaudhry was originally UNIT UK’s Press and PR Officer, but was promoted to the role of Commanding Officer after Brimmicombe-Wood’s treachery was exposed.
Colonel Alan Mace
c.2007 – 2009
The first UNIT commander we see in the new series of Doctor Who is Colonel Alan Mace, who we meet in “The Sontaran Stratagem”; a story set in 2009. We are given no indication of how long he has been in charge of the UK contingent prior to this; however, he appears to be in charge of UNIT during the Racnoss incursion of Christmas 2007, as seen in “Turn Left”. It is entirely feasible that he took over from Colonel Chaudhry sometime between 2005 and 2007.
Colonel Augustus Oduya
2009 – Early 2010s
Colonel Oduya appears in Torchwood “Children of Earth”. Dialogue suggests that he succeeded Colonel Mace, who is said to have been posted to Vancouver. This story is dated to September 2009. We do not know how long he lasted in the role.
The next time we see UNIT on screen (In “The Power of Three”) we are told that Kate Stewart, the daughter of Brigadier Lethbridge-Stewart, is now in overall charge of the organisation. However, Kate is a scientist, in charge of UNIT’s scientific research; the military side of UNIT would still have a Commanding Officer (it is unlikely that any military organisation would suddenly relinquish their authority to a civilian).
The new series of UNIT audios, beginning with “UNIT Extinction” introduces us to the character of Colonel Shindi. These stories are set between “The Power of Three” and “The Day of the Doctor”, so we can tentatively date them to 2012 or 2013.
The character of Colonel Ahmed appears as the highest ranking UNIT officer aboard Boat One in “Death in Heaven”. However, he is killed by the Cybermen.
Colonel Walsh was in command of a contingent of UNIT troops in Turmezistan in “The Zygon Invasion”, however, we can safely assume that she is a British officer (or, at the very last, an officer in a Commonwealth army) because both she and Major Hitchins wear British rank insignia.
Colonel Tia Karim
The Sarah Jane Adventures introduced us to the character of Colonel Karim, but I personally do not count her as one of UNIT’s COs (despite her being referred to as a Colonel), simply because I prefer to think of her more as the Officer Commanding UNIT’s Mount Snowden Base (plus her rank insignia displays the pips of a Lieutenant not a Colonel). Thankfully, it is not stated in the episode that she is UNIT’s Commanding Officer, so my theory doesn’t contradict on screen evidence.
Personally, I think that these days whenever the Doctor Who writers need a military character in a position of authority they seem to just plump for a Colonel, regardless of how realistic this would actually be. It is perhaps my biggest criticism of NuWho that there doesn’t seem to be anyone who actually understands how a military organisation works (the same criticism can be levelled at Sherlock – there are so many mistakes it brings me right out of the narrative!).