The phrase "Press Gang" has its origins in naval terminology, and is specifically associated with the Royal Navy in the 17th and 18th Centuries. "Pressing" was probably going on long before then, however.

Members of "Press Gangs", or "The Impress Service" as it was formally known, could be found in most ports and were a group of men who would tour the locality looking for suitable candidates for the Royal Navy, whom they would abduct into service. This was all perfectly legal and above board because the Royal Navy was viewed as an essential service which needed 'recruits' desperately. So, one minute you're staggering down the road on the way home from the pub with a belly full of ale, the next you're off to sea.