Persons who committed capital offences were required to travel to England for trial, and no judicial officers were present in Newfoundland during the winters.
By 1720, this situation had led to a high crime rate in St. John's and the British government appointed Keen as the first "winter" justice of the peace who would conduct judicial business while the fishing Admirals were away.
In practice, Governor Henry Osborn allowed Keen and the other justices of the peace who were appointed to hear cases year round.
There were many disputes between the justices of the peace and the fishing Admirals, and Keen became the leader of a movement to officially establish a permanent judiciary in Newfoundland.
In 1750, the British government decided that justices of the peace in St John's could sit in judgment as "commissioners" over all cases except treason, although they could only do so if the governor was present in Newfoundland.