Originally from Horsley, Gloucester, Williams was working as a canal boatman on the Brecon to Monmouth in Wales under the pseudonym William Cross when he and Johns were arrested on 15 November 1848 near Chepstow for "... illegally entering the premises of Mr Richard Price, Esquire, of Pentwyn Clydach... and from there taking three loaves of bread, one piece of bacon, several cheeses, a kettle and a quantity of salt".
Newspaper reports of the trial suggest that the pair gave an unexpectedly spirited defence, but Johns was abrasive and "contravened the conventions of court procedure".
Edgar (1990) observes that in several other cases brought before the same judge that day, guilty pleas to very similar charges resulted in sentences ranging from three weeks to three months.
On 1 January 1850, they were transferred to Pentonville Prison to serve their mandatory six months of solitary confinement.
Williams remained at Dartmoor until March 1852, when he boarded the Fairlie for transportation to Van Diemen's Land.