St. Cedd's College, Cambridge
It is the home of Professor Chronotis, a retired time traveller who appears in Adams' fiction, and—in the fictional universe—was also the college of Isaac Newton (who attended Trinity) and Samuel Taylor Coleridge (who attended Jesus). It was named after Saint Cedd, brother of Saint Chad (after whom St Chad's College, Durham is named), whom Gently describes as "one of the duller Northumbrian saints."
It is based somewhat on Adams's own college, St John's. For Shada, scenes at St. Cedd's were filmed on location at Emmanuel College. In a 2012 episode of the TV adaptation Dirk Gently, Wills Hall at the University of Bristol was used as St. Cedd's College instead.
St Cedd’s College ... owes a little to my memories of St John’s College, Cambridge, although I’ve also borrowed indiscriminately from other colleges as well. The point is that St Cedd’s College is a completely fictitious assemblage, and no correspondence is intended between any institutions or characters in this book and any real institutions or people, living, dead, or wandering the night in ghostly torment.
St. Cedd's College is also mentioned in the Torchwood online game, made during the show's second series. It is said to be the college attended by Dr. John Winters, a fictional character within the game.