In December 1796 he was appointed commander in Ulster and issued a proclamation ordering the surrender of all arms by the civil population, during which time he was 'untroubled by legal restraints or by his troops' violent actions'. Historians have generally seen Lake's "Dragooning of Ulster" in 1797 as effective in disarming and crippling the Society of United Irishmen in that province, although his effectiveness has been questioned. Lake succeeded Sir Ralph Abercromby as commander-in-chief of British troops in Ireland in April 1798 and turned his attention to Leinster, where 'public floggings and torture of suspected rebels became widespread and added to the general atmosphere of terror'. Rather than cowing the province into submission, 'his crude methods probably contributed to the outbreak of insurrection' in May 1798. Lake continued to deal harshly with opposition, and issued orders to take no prisoners during the rebellion.