Green’s Dictionary of Slang

Uncle Fred n.

bread.

1932		‘P.P.’ Rhy. Sl.
1960		J. Franklyn Dict. of Rhy. Sl.
1971		J. Jones Rhy. Cockney Sl.
1979		R. Barker Fletcher’s Book of Rhy. Sl. 25: A loaf of Uncle Fred.
2001		M. Coles Bible in Cockney 124: Guv, please give us some Uncle Fred.