GM was a UK magazine that was published by Croftward Publishing between 1988 and 1990. The magazine used the strapline "the Independent Fantasy Roleplaying Magazine" and it lasted for 19 issues. It and was the succeded by GamesMaster International.
Sample Covers
GM volume 1, issue 11 (July 1989)
References
[1], wikipedia, "G.M. The Independent Fantasy Roleplaying Magazine"