Green’s Dictionary of Slang

a street-seller of ice-cream.

1909

J. Ware Passing Eng. of the Victorian Era 97/2: Cream Ice Jacks (London Streets). Street-sellers of ½d. ices. Jacks probably from Giacomo and Giacopo. ‘They’ve a bad time of it, ’ave the cream ice Jacks, for whenever a kid gits ill the mother goes for the jack an’ ’as it out with ’im.’.