The Daddy. Terminology for hardest, most respected nut in Borstal. For complete definition see Ray Winston in the film 'Scum'.
Ray Winston, "Did bring your fackin' tool?"
Big Inmate, "What fackin' tool?"
RW, "This fackin' tool."
BI, "Uuhhnnnnn, uuhhnnn, argh."
RW, "I'm the Daddy now."