Green’s Dictionary of Slang

licence n.

In phrases

where did you get your licence? (also where did you get a ticket?)

(Aus.) a general excl. of annoyance aimed at a poor or allegedly poor driver, often with a suggestion such as ‘Woolworths?’ ‘Off a Weetabix packet?’ etc.

C. Simpson New Aus. 110: Our taximan leans out of his window: ‘And where did you ever get a bloody driver’s licence – out of a Weetbix packet?’.
[Aus]Sun-Herald (Sydney) 4 Apr. 87: The bloke beside me yelled out. .. ‘Where’d you get a ticket, ref, out of a cornflakes packet?’ [GAW4].
[Aus]P. Vautin Laughing at League 137: Sam stood up, gave his head a quick shake and said to the driver, ‘Eh, where did you get your licence, brother – out of a box of Coco Pops?’ [GAW4].
Primrose & Wheeler Green Show Script [Internet] Voices of Motorists ‘Get off the road grandpa!’ ‘Wanker!’ ‘Road-Hog!’ ‘I’ve seen snails with more speed than you!’ ‘Where did you get your license from? The back of a Weet-bix packet!’.
[US]Middletown Church of Christ (Louisville KY) ‘Life in the Fast Lane’ [Internet] I am running late! I’m behind! Gotta get there fast! Gotta keep moving! Slowpoke driver, get out of my way! HONK!HONK! Where did you get your license, out of a Cracker Jack box? I’m late! Gotta get there fast! Gotta keep moving!
[NZ]McGill Reed Dict. of N.Z. Sl. 229: Where’d you get your licence, out of a Weet-Bix packet? You are a bad driver.