The Library of St. John the Beheaded is an institution in the fictional world of Doctor Who. Created by Andy Lane for his novel All-Consuming Fire, it is described as being under the control of the Catholic Church which uses the Library as a depository for banned literature.
In a further development of the concept, the Big Finish Productions audio play Neverland written by Alan Barnes, makes mention of 'The Knights of St John the Beheaded' whose Earthly myths make reference to the Gallifreyan legends of Rassilon and his battle with the beast Zagreus.
The Library of St. John the Beheaded Wikipedia
The Library is located in Holborn between the Church of St Giles, London and the Seven Dials district, which was also used as a setting for crime stories by Arthur Conan Doyle and Agatha Christie as it was one of London’s ancient ‘rookeries’, tightly packed slums of poverty and lawlessness.
The Library was one of several recurring locations employed by the authors of the Virgin New Adventures; others include a house in Allen Road, Kent, and an asteroid housing the Braxiatel Collection which had its origins in a casual remark made on television and which gave rise to the recurring character of Irving Braxiatel.