Ipso Facto was a science fiction fanzine edited by george Locke and published by Ted Forsth and Joe Patrizio in London, England.
Released in April 1961, Ipso Facto was the official organ and the first compilation fanzine of the British apa, The International Publishers Speculative Organisation. It consisted of analytical comments on fantasy apas.
The apa was initiated by John Berry and George Locke in November 1960. George Locke was the OE. The International Publishers Speculative Organziation lasted for three years, with the seventh and final mailing put out in September 1963 by Los Angeles fan Fred Patten.
Contributors were John Berry (Pot Pourri), Bruce Burn, F.M. Busby (Cry of the Nameless), Bill Donaho (Habakkuk, Viper), Ron Ellik (Shangri L'Affaires), Ted Johnstone (Shangri L'Affaires), Robert Lichtman, Ethel Lindsay (Scottishe), George Locke (Smoke), Ed Meskys (Niekas), Norm Metcalf, Len Moffatt (Shangri L'Affaires), Joe Patrizio, Bruce Pelz, Alan Rispin, and Ella Parker (Orion).
Skyrack #33 of June 1961 said, "Quite a line-up!"