The Service

The Service was the otherwise-unnamed secret service of the British Empire. It was founded during the reign of Elizabeth I by spy-magician John Dee and Francis Walsingham, and 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 organization were hidden in obscure offices at Westminster.

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)

Nate Silver's friend and comrade-in-arms 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 had been handed to mundanities and mediocrities.

In the 17th century, Dr. Alex Bendo was one of the Five Masters; later, Jeova Unus Sanctus became Master and invited Nate Silver to become the unofficial "Master of Masters" and lead the world to become the Republic of Heaven. but (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 Revolutionary War, it consumed most of England's intelligence budget. In 1782, Sabbath's assassin Tula Lui murdered three of the Five Masters.

Lisa-Beth forced the Service to attend Scarlette's wedding to the Doctor by threatening to publicly release the five secret names of the Points of the Star. (PROSE: The Adventuress of Henrietta Street)

Alternate timeline
In an alternate timeline created by the Oracle, the the Service was called the Security Service. Twenty-one-year-old Sabbath faced his final initiation 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)