Katherine Harmonica Joy Catherine "Mimi" Tutton (née Murphy, previously Maguire; born 4 October 1963) is a fictional character from the Channel 4 drama Shameless. Mimi is the foul-mouthed, loud, brash and violent matriarch of the Maguire family. She is also a drug dealer on the Chatsworth Estate and is frequently seen selling drugs on the show. She is extremely violent and easily angered. She has "headbutted" several characters on the show including Lip Gallagher, Sue Garland, Cassie Western and even her own son Shane. Mimi is as hard as nails, and she can hold her own with men and women; at one point during series 3 a whole riot squad is needed to restrain her after she attempts to free her daughter from incarceration at the police station.