 During 1301, St John was warden of Galloway and the sheriffdom of Dumfries, as well as of the adjacent marches.In the spring of that year he was appointed, with John de Warenne, Earl of Surrey and others, to treat at Canterbury of a peace between the English and the Scots with the envoys of Philip IV of France.In January 1301 St John was at the Lincoln parliament, and signed the Barons' Letter of 1301 to the pope, although not himself a baron, never having been summpned by writ to parliament.