In 1644 he held a command in the artillery under Essex in Cornwall and took part in the surrender after the second Battle of Lostwithiel (2 September 1644). Essex ("Letter to Sir Philip Stapleton, Rushworth Collection") calls him "an honest, judicious and stout man", an estimate of Deane borne out by Clarendon's "bold and excellent officer" ("book xiv. cap. 27"), and he was one of the few officers concerned in the surrender who were retained at the remodelling of the army.