Muriel Frost

Captain (later Colonel) Muriel Frost worked for UNIT. On a number of occasions, she worked with the Doctor's seventh incarnation. She was later killed by the Slitheen family, with her loss being felt by UNIT, especially by those close to her.

Biography
In 1980, as a UNIT Captain, she met with Scalini at Pompeii, where the Professor had discovered a police box buried in the ruins. (AUDIO: The Fires of Vulcan)

Working undercover, Frost investigated Stranks, the owner of a night club suspected of selling a potent street drug called Mandrake. At the same time, the Seventh Doctor and Ace had been drawn to Earth by the alien energy structure known as the Mandragora Helix. It had contacted Stranks and used him to produce Mandrake, which sapped the will of its users and made them susceptible to the Helix's influence. The Doctor and Ace worked with Frost to thwart the Helix again. During the course of this venture, she received a field promotion to Colonel. (COMIC: The Mark of Mandragora)

Muriel had a troubled relationship with her boyfriend, Nick. She loved him, in spite of how much they fought, trying to make things better better between them, but he never reciprocated those feelings, often inciting their arguments in the first place. Ultimately, she knew that the relationship wasn't healthy. (COMIC: Evening's Empire)

In the 1990s, she, Corporal Ives and UNIT helped the Seventh Doctor investigate a crashed Nazi plane from World War 2 in Middlesbrough, which the Doctor suspected had something to do with a UFO. She and two other UNIT personnel did a dive to the bottom of a river, finding the plane quickly, though Frost had a feeling it was waiting for her. Meanwhile, Ace was kidnapped by Alex Evening. That evening, the plane was removed from the river, and the body of the dead pilot was brought to a secure place, and Frost was wired up to a machine, built by the Doctor, to let her talk to te deceased pilot. The experience was tough for her, as the German pilot was able to read her mind, becoming privy to her tough relationship. Afterwards, she was able to confirm that there was a UFO involved, but she also wanted to destroy the machine. (COMIC: Evening's Empire)

Major Jenny Maguire evidently knew Muriel Frost on a personal basis prior to her death. (PROSE: Operation London, Number Ten)

After the London UFO crash on 6 March 2006 (TV: Aliens of London) or 28 June 2006, (PROSE: Operation London) Frost and her Geneva EVA team (PROSE: Number Ten) were summoned to 10 Downing Street (TV: Aliens of London) from Geneva. (PROSE: Operation London) She was summoned to be an advisor on extraterrestrial activity, coming dressed in her US Army Major uniform. However, she was killed by the Slitheen family who had infiltrated Earth's government. (TV: Aliens of London) Major Jenny Maguire shortly after officially announced her and her team's death on an operations board to other UNIT officers. She had to inform the families of the deceased, and later saw the coffins off an air strip. (PROSE: Number Ten)

Other timelines
In a world where humans had a working relationship with the Silurians, Frost was a member of URIC, that world's equivalent to UNIT. (COMIC: Final Genesis)

Personality
Fiery in both hair colour and temperament, Frost was a no-nonsense and efficient UNIT operative who had problems maintaining personal relationships. (AUDIO: The Fires of Vulcan) Even when faced with deeply horrific scenarios, Frost acted like a "warrior", not giving in to fear. (COMIC: Evening's Empire) Major Jenny Highway, who was familiar with Frost, joked that "[she would] like to see anyone face her down", referencing her temperament. (PROSE: Operation London)

Appearance
Fairskinned and slim built, (COMIC: Evening's Empire) Frost had distinct firey-red hair, (COMIC: Evening's Empire, AUDIO: The Fires of Vulcan) with an angular face complete with arching eyebrows and prominent cheekbones. (COMIC: The Mark of Mandragora, Evening's Empire, TV: Aliens of London) She had either blue (COMIC: Evening's Empire) or brown eyes. (TV: Aliens of London) She had ear piercings. (COMIC: The Mark of Mandragora, TV: Aliens of London) By the time of Frost's death, however, she had black hair. (TV: Aliens of London)

Behind the scenes

 * In early drafts of 2005's Aliens of London, the Ninth Doctor specifically named one of the uniformed characters as Muriel Frost. (REF: DWMSE 11) In the final cut of the episode, the nametag "FROST" is still visible on her uniform.
 * PROSE: Operation London and Number Ten, two short stories that were released to coincide with Aliens of London and World War Three, explicitly references Frost by her surname.
 * The 2005 Classified! A Confidential 3-D Dossier activity book included a closing note from General Muriel Frost.