| Mycroft Holmes |
|Parents|| Mr Holmes (father)|
Mrs Holmes (mother)
|Siblings|| Sherlock Holmes (brother)|
Eurus Holmes (sister)
|Family||Rudolph "Rudy" Holmes (paternal uncle, only mentioned by Mycroft)|
|Occupation||Government official, "the British Government"|
|Behind the scenes|
|Portrayed by||Mark Gatiss|
- Mycroft: "For goodness' sake! I occupy a minor position in the British Government."
- Sherlock: "He is the British Government – when he's not too busy being the British Secret Service or the CIA on a freelance basis. Good evening, Mycroft. Try not to start a war before I get home, you know what it does for the traffic."
- ―A Study in Pink
Mycroft Holmes is Sherlock Holmes' brother and is traditionally older by seven years. It is mentioned in "The Final Problem" that, along with tradition, he remains seven years Sherlock's senior in the BBC adaption. 
Mycroft claims to merely "occupy a minor position in the government". However, according to Sherlock, he functionally is the British Government, acting as the control centre or "clearing house" for all government actions and decisions. Mycroft tells John in the pilot that Sherlock may even consider him his arch-enemy. Sherlock neither confirms nor denies this statement.
There are signs throughout the series that Sherlock Holmes is right about Mycroft's high position in the UK Government, such as his ability to control CCTV cameras at will. He also is shown to have the ability to hack into cash machines and make them display messages he wants the user to see. Reflecting his high position is his priority level "Ultra" and clearance level higher than the Cabinet Office or even the Prime Minister: him and a group of peers with certain codenames are the only people to know what really happened at Appledore and doctored the footage that will go public and even managed to clear Sherlock of his crimes. He is also implied to have a great say over certain policies: the fact that the British Government stopped using freelance agents for high-risk missions after the incident in Tbilisi is his initiative. With his priority level, he has access to MI5's top secret archives.
Mycroft has a habit of kidnapping people to talk to them, instead of using more conventional methods. He has very good connections; it is implied by Sherlock that he knows the Queen, when Sherlock starts to play "God Save the Queen" on his violin, and he is able to pull strings to allow Sherlock access into a top secret military base. In this episode, it is also asserted that his priority level is "Ultra". Unlike his brother, Mycroft is known to only text when he cannot talk.
Mycroft occasionally warns John when he thinks that it is a "danger night" with Sherlock ("A Scandal in Belgravia"), and has John search the house. On those nights, he needs John to stay at home with Sherlock and look out for him. However, Sherlock knows that John has been searching his stuff, and may be aware of what Mycroft has done (and what he has asked John to do).
Abilities & Personality Edit
- "Balance of probability, little brother."
- ―Mycroft to a young Sherlock [src]
Despite the hostility/rivalry between them, Mycroft cares greatly for his brother, although his ways of watching out for his brother are unorthodox in the extreme. He is an almost entirely cynical, socially detached, and calculating individual with an exceptional degree of self-control.
His powers of deduction surpass that of his younger brother, Sherlock, when he discovered what had happened to a hiker by simply "glancing over the police reports". At one point, he and Sherlock have a deduction battle and, as always, he wins. He has always been 'the smart one' according to them both, which caused Sherlock to believe that he was an idiot, until they met other children. For example, Mycroft corrects Sherlock's deduction of John and the lilo, by saying it was the sofa, and was able perceive that Alex Garrideb was short-sighted but had corrective laser surgery, which Sherlock's deductions had missed. However, despite being more intelligent, Mycroft is also shown to be lazier and sets others to do his work for him although he could do it himself. It is a recurring joke that this is because it requires, "legwork", something that he is not very keen on. Nonetheless, Mycroft's analytic abilities are incredible, beyond the standards of Charles Augustus Magnussen himself, despite the fact that Mycroft relied on the latter most heavily. However, Mycroft's intellect, while professionally assessed as 'remarkable', was surpassed by his younger sister Eurus Holmes who was an era-defining genius beyond Newton, able to perceive things beyond even Mycroft's own scope. Because of his own intellect, Mycroft is one of the very few people in the world who could safely interact with Eurus without becoming subject to her gift at manipulation.
After he has first witnessed Sherlock and John working together, he tells his assistant to update Sherlock and John's surveillance status to level 3, implying that he already had governmental surveillance on Sherlock. In tandem with his high intelligence, his self-confidence and mental resilience are almost inhuman, as he seems to be practically immune to even his own brother's probing and he was even able to resist eurus own ability to instantly reprogram person despite eurus being more intelligent. He is however, not above petty or childish arguments with Sherlock, claiming that their hostility was upsetting their mother with Sherlock claiming that he wasn't; he also argued with Sherlock in front of one of his peers and John in Buckingham Palace to force him to wear pants. Like Sherlock, Mycroft also smokes cigarettes albeit at a lesser rate and less often, with him carrying a pack at any moment and can also enjoy chatting over smoking, usually without his parents finding out.
Mycroft is shown to be much more capable of faking or maintaining a degree normalcy than his brother, and where as Sherlock is ostracized for his behaviour, Mycroft is highly respected by his (seeming) peers. Though Mycroft is apparently just as cold as his brother, once informing him categorically that caring was not an advantage, he still strongly reacts to the human loss of life. As seen in his forced part in Eurus's game at Sherrinford, he refuses to take the life of Sherrinford's governor when offered the gun, felt the condemnation game over the lives of the three Garrideb brothers to be insane and inhuman, worried over the imminent death of Molly Hooper's life, and acted to preserve the lives of the people in the city which were threatened by the 'plane' that Eurus had set up.
He is thought to be very lonely and isolated. Sherlock has said this to him too, as even Sherlock has friends but Mycroft has none. Mycroft believes himself to be "living in a world of goldfish", showing how he believes himself to be surrounded by people of much lower intelligence.
However, despite his lack of romantic interests, it is suggested that he is not a virgin unlike his brother Sherlock. When in Buckingham Palace, upon telling his brother not to be alarmed as Irene Adler's job was to do with sex, Sherlock replied "Sex doesn't alarm me", to which Mycroft sarcastically asked him "How would you know?". To make up for his accusation of treason, Lady Smallwood has taken up Mycroft on this regard. On other occasions, Irene Adler had informed the Holmes brothers that Moriarty's nickname for Mycroft was "The Iceman" whereas his nickname for Sherlock was "The Virgin". Also, during the wedding of John and Mary, Sherlock had phoned Mycroft just after Mycroft had finished exercising and asked him why he was out of breath. He then stated that he had either caught Mycroft in a 'compromising position' or he had been working out again. He might work out primarily to keep his body healthy and thus his mind sharp as it seems he is quite physically weak. This is demonstrated when he condescendingly referred to Sherlock as "brother mine" and Sherlock effortlessly twisted his arm up his back. John even warned Mycroft that Sherlock could easily injure him severely and Mycroft reluctantly departed, indicating he is capable of picking and choosing his confrontations, a trait Sherlock either lacks or dismisses.
Again, despite his seeming lack of empathy, he still cares greatly about his younger brother Sherlock as seen in the first episode, when he had informed John that he "worries about him constantly". When surprised by a home video of Sherlock and himself as young children on the beach, Mycroft uncontrollably smiled as young Sherlock ran up to his younger self and tackled him with a hug. In another episode, Sherlock and Mycroft are seen to be smoking outside their parents' house on Christmas day, where Mycroft says to Sherlock "Your loss would break my heart". He often appears in Sherlock's mind palace to offer assistance and insults, reflecting his status as the older brother smarter than Sherlock. In Eurus's last game at Sherrinford forcing Sherlock to choose between killing Mycroft and John in order to be granted another chance at saving the 'plane' from crashing into the city, Mycroft, despite the asset his superior intellect would contribute, tries to manipulate Sherlock into killing him over John, a gesture that Sherlock himself recognized and made it even more harder for him to raise the gun.
In contrast to his relationship with Sherlock, Mycroft's feelings to his youngest sister Eurus was more estranged. Though he recognized the outstanding genius of her superior intellect, Mycroft was aware of Eurus's disturbing personality and actions. Aware of the dangers posed by his sister's psychosis coupled with her abilities, Mycroft supported Eurus's secret institutionalization at Sherrinford with their Uncle Rudi's help. Mycroft regards Eurus as a danger first and foremost and conducts himself accordingly, being resistant and unwilling to becoming subject to her manipulations. The mere mention of her, and recalling memories of Eurus, brought even higher guard and dread than even Charles Augustus Magnussen's name. In turn, Eurus had a singular preference for Sherlock and seemingly holds Mycroft with no regard beyond Sherlock's attachment to Mycroft and in comparison with Sherlock's attachment to John. Despite this, Mycroft does hold a measure of sentiment for his youngest sister, occasionally speaking to Eurus and exchanging consultations with her genius insight with 'treats' such as a violin and, despite the extreme danger that may and did come out of it, a genuine unsupervised conversation with Jim Moriarty for five minutes. Though his mother abhorred Mycroft's actions of secretly institutionalizing Eurus for decades, Sherlock recognized that Mycroft had did his best considering everything regarding Eurus. Years later, Mycroft and his parents sat at Eurus's violin recital with Sherlock.
Mycroft also harbors a love for vintage cinema in his home, silently quoting the lines by one of the leads.
- "My brother has the brain of a scientist or a philosopher, yet he elects to be a detective. What might we deduce about his heart?"
- ―Mycroft to John [src]
- "Too much history between us, John. Old scores. Resentments."
- ―Mycroft to John [src]
- "Nicked all his Smurfs? Broke his Action Man?"
- ―John to Mycroft [src]
- "If you seem slow to me, Sherlock, can you imagine what real people are like? I'm living in a world of goldfish."
- ―Mycroft to Sherlock [src]
- "I am the smart one."
- ―Mycroft to Sherlock [src]
- "Mycroft is the name you gave me, if you could possibly struggle all the way to the end."
- ―Mycroft to his mother, when addressed by her as "Mike"
- "Both of us thought you were an idiot, Sherlock. We had nothing else to go on, until we met other children."
- ― Mycroft to Sherlock
- He is on a diet, which Sherlock comments about frequently. Mycroft is also made fun of for his working-out.
- He wears a ring on the ring finger of his right hand. It is unknown if this is symbolic of anything. Show co-creator and actor of Mycroft, Mark Gatiss, has stated that it is not a wedding ring, but that he likes to think there is a story behind it. It has also been stated that it was because Gatiss did not wish to take off his wedding ring, which is why Mycroft sports it. 
- He does not appear during the "Unaired Pilot", and his lines during the ending scene are given to DI Greg Lestrade.
- Mycroft is a member of the Diogenes Club, a private establishment that requires silence at all times, as in the canon.
- Irene Adler revealed that Jim Moriarty's nickname for him was "The Iceman".
- He and Sherlock has a third sibling, as he was speaking to another government official about the country needing Sherlock Holmes. As he dismissed the official about feeling sentiment for Sherlock, he briefly told the official "You know what happened to the other one". In Series 4, their third sibling was revealed to be a sister, Eurus Holmes.
- It is heavily suggested that Mycroft might just be smarter than Sherlock in many respects, his presence in Sherlock's mind palace after the latter was shot corroborates this even further.
- He is considered by those in his rarefied circle to be the most powerful person in England.
- Sherlock tells John that Mycroft has OCD.
- Mycroft is fluent in Serbian. He appears to be very adept at learning languages, claiming to learn Serbian in only a few hours.
- In any case of death for Mycroft, he would prefer not to be shot in the head, as he had promised his brain for the Royal Society.
- ↑ 1.0 1.1 Moffat, Steven (writer) & McGuigan, Paul (director). (25 July, 2010). "A Study in Pink". Sherlock (2010). Series 1. Episode 1. BBC One.
- ↑ Thompson, Steve (writer) & Haynes, Toby (director). (15 January, 2012). "The Reichenbach Fall". Sherlock (2010). Series 2. Episode 3. BBC One.
- ↑ 3.0 3.1 3.2 Moffat, Steven (writer) & McGuigan, Paul (director). (1 January, 2012). "A Scandal in Belgravia". Sherlock (2010). Series 2. Episode 1. BBC One.
- ↑ Gatiss, Mark (writer) & McGuigan, Paul (director). (8 January, 2012). "The Hounds of Baskerville". Sherlock (2010). Series 2. Episode 2. BBC One.
- ↑ 5.0 5.1 5.2 Gatiss, Mark (writer) & McGuigan, Paul (director). (8 August, 2010). "The Great Game". Sherlock (2010). Series 1. Episode 3. BBC One.
- ↑ 6.0 6.1 Gatiss, Mark (writer) & Lovering, Jeremy (director). (1 January, 2014). "The Empty Hearse". Sherlock (2010). Series 3. Episode 1. BBC One.
- ↑ Thompson, Steve; Moffat, Steven; Gatiss, Mark (writers) & McCarthy, Colm (director). (5 January, 2014). "The Sign of Three". Sherlock (2010). Series 3. Episode 2. BBC One.
- ↑ 8.0 8.1 8.2 Moffat, Steven (writer) & Hurran, Nick (director). (12 January, 2014). "His Last Vow". Sherlock (2010). Series 3. Episode 3. BBC One.