The Order of Saint Francis of Mendenham, informally known as the Hellfire Club, was a secret occult organisation of politicians, businessmen, and other powerful people.
The club was created to mock the prevalent religion of the time. Sir Francis Dashwood continued the tradition in the 1750s. The Eighth Doctor described them as "simply a group of chums who spent weekends with him at Medmenham from time to time", dismissing the possibility of their involvement with human sacrifices or "pacts with anyone called Lucifer." (AUDIO: Minuet in Hell)
In 1762, Mary Culver, a member of the original Hellfire Club, ritually slit her own throat with a piece of broken glass, (PROSE: The Adventuress of Henrietta Street) completing the Supplication of the Anakim and becoming a host for Compassion. From the whispering gallery of St Paul's Cathedral, she directed Lord Sandwich in the affairs of the Club. (AUDIO: Sabbath Dei)
The Club fell into disrepute in the 1760s and faded into obscurity (AUDIO: Minuet in Hell) by 1770. (PROSE: The Adventuress of Henrietta Street) In the following decades it was sporadically reformed by various people making serious attempts at summoning arcane beings. (AUDIO: Minuet in Hell)
Scarlette, the proprietress of the Henrietta Street House, was the last Madam of the Hellfire Club. She represented the Club at the Eighth Doctor's wedding in 1782 and used her arcane knowledge to help defend Earth from an invasion of Babewyns. (PROSE: The Adventuress of Henrietta Street)
There was a version of the club in London at the end of the 19th century. Henry Gordon Jago and Henry Gordon Jago Jr found the dead body of Ruby Valentine there. After Jago Jr was kidnapped, Jago went there to find him. Jago and Litefoot found a menagerie in the building. It contained a coffin of an alien being. (AUDIO: Jago & Son)
By 2003 a new Hellfire Club had been set up in Malebolgia to assist in electing Brigham Elisha Dashwood III as their first Governor, and to continue the drinking and debauchery of their predecessors. Dashwood summoned the demon Marchosias, but the subsequent invasion of Psionovores was prevented by the Eighth Doctor. (AUDIO: Minuet in Hell)
In an alternate history where Sebastian Grayle achieved immortality, the Eighth Doctor and Charlotte Pollard arrived in Wycombe Caves in 1806. Grayle had set up the Hellfire Club as a psychic conduit for summoning the Nimon to Earth. The Doctor and Charley interfered with Grayle's plans and stopped the invasion, but not before the Nimon had consumed most of the current membership. (AUDIO: Seasons of Fear)