Mark Foster, known as MRK1 (formerly Mark One), is a dubstep, grime and bass music producer, originally from Manchester, England. He is known especially for his work with the Virus Syndicate, including MCs Goldfinger and Nika D, which he produces and provides instrumental tracks for, and his fusion of both genres.

MRK1 has been producing music for over last 10 years. He began making dnb and then progressed into Dubstep/Grime and more recently has seen him branch out into all genres of bass music.