Green’s Dictionary of Slang

(S.Afr.) a nickname for the Roeland Street prison, Cape Town.

1956

A. Le Guma in New Age 27 Sept. 6: In Roeland Street, Cape Town [...] stands the mass of brick and stone which is the city jail [...] Hardened old-timers refer to it with macabre humour as ‘Oubaas,’ and behind its walls exists a world ruled by stony-eyed guards who have become as cold as the iron bars over the windows [DSAE].