The Service was the otherwise-unnamed secret service of the British Empire.
It was founded in the late 16th century by Francis Walsingham and spy-magician John Dee. Its spymasters were known for their occultist tendencies. It was nominally led by the Five Masters of the Council of the Star Chamber, although the real heads of the organisation were hidden in obscure offices at Westminster. (PROSE: The Adventuress of Henrietta Street)
Giordano Bruno worked for the Service while staying in England in the 1580s. After meeting with Father Self in 1584, Bruno shared his mnemonic system with colleagues in the Service who were later hypnotised by Self to contribute their memories to Bruno's remembrance. (PROSE: De Umbris Idearum)
While less-trusted agents were used mostly just for intelligence gathering, higher-ranking Servicemen were trained extensively in disguise, espionage, and occultism. These agents were so powerful that the Service, following the precedent of Dee's Enochian brainwashing techniques, promoted its own mysticism to keep the Servicemen loyal to the idea of something greater than itself. In 1760, the Ratcatchers were founded to enforce this brainwashing. (PROSE: The Adventuress of Henrietta Street)
Don Taylor joined the Service after the English Civil War. He said there was Roman magic in its rites and described it as "Gloriana's secret order, first entrusted to Walsingham and Dee." However, under the guidance of "General Warts-and-all", he said the Service was led by "mundanities and mediocrities". (PROSE: Newtons Sleep)
The Service was revamped at the start of the reign of George II, whose court was filled with occultists and Freemasons. By the time of the American War of Independence, it consumed most of England's intelligence budget. In 1782, Sabbath's assassin Tula Lui murdered three of the Five Masters.
Lisa-Beth Lachlan forced the Service to attend Scarlette's wedding to the Eighth Doctor in 1783 by threatening to publicly release the five secret names of the Points of the Star. (PROSE: The Adventuress of Henrietta Street)
Alternate timeline Edit
In an alternate timeline created by the Oracle, the organisation was called the Security Service. Twenty-one-year-old Sabbath faced his final initiation into the Security Service in 1732, rather than 1763 as in the real universe. While the Eighth Doctor was in that timeline in 2003, he was manipulated by Security Service agent Hannah Baxter to help her uncover leaders in the government resistance movement. (PROSE: The Domino Effect)