Lacey's final award for outstanding service during 1940 was a Mention in Despatches announced on 1 January 1941. Lacey was commissioned a pilot officer (on probation) on 25 January 1941 (seniority from 15 January) and promoted to acting flight lieutenant in June. On 10 July 1941, as "A" flight commander, he shot down a Bf 109 and damaged another a few days later on 14 July. On 17 July, he claimed a Heinkel He 59 seaplane shot down and on 24 July, two Bf 109s (by causing them to collide). He was posted away from combat operations during August 1941, serving as a flight instructor with No. 57 Operational Training Unit. He was promoted to war substantive flying officer on 22 September.