Mark Foster, known as MRK1 (formerly Markone or Mark One), is a dubstep and grime producer from Manchester, England, originally a drum n bass artist. 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. He has worked with Trim (from the Roll Deep crew), Jammer, Ears, Poet Shado, and Flirta D. He is currently signed to Planet µ records. He has appeared in Mixmag magazine, and was nominated as "Best Grime" producer at the 2003 Sidewinder awards. MRK1 has also appeared on Science Faction: Dubstep (as Mark One), a notable dubstep compilation which featured artists such as Loefah, Distance, Pinch, Search and Destroy, DJ Hatcha, and Benga.
His name is inspired by television channel BBC One.