On graduation, Spencer joined the
Royal Warwickshire Regiment, and then transferred to the
Royal Engineers, commissioned from acting lance corporal to second lieutenant on 20 December 1939. In February 1941, due to the losses of pilots during the
Battle of Britain, an Army Council Instruction was issued to state that
British Army personnel could apply to transfer to the
Royal Air Force (RAF), which 18,000 officers took up.
RAF service Spencer transferred to the
Royal Air Force Volunteer Reserve (RAFVR) and was commissioned on 10 October 1941 (RAF No. 47269). He completed his entire flying training in the United Kingdom, and was a flying officer by the time of his posting to his first operational unit,
No. 26 Squadron RAF at Gatwick, in November 1942. In June 1943, Spencer was promoted to Flight Commander of the unit, and four months later to
flight lieutenant. Having spent 15 months with No. 26 Squadron, he was posted to
No. 165 (Ceylon) Squadron at Culmhead as a Flight Commander at the beginning of February 1944, flying Spitfire IXs. Spencer was posted to
No. 41 Squadron RAF as Officer Commanding A Flight, on 28 May 1944, where he flew
Supermarine Spitfire Mk. XIIs. Between 23 June and 28 August 1944, he claimed seven
V-1 flying bombs destroyed, but an eighth is also recorded in his logbook that did not make it to the official records. One of these he succeeded in destroying by tipping it up with the wing of his aircraft, an event sketched into his logbook by fellow pilot and amateur artist, Flight Lieutenant Tom Slack, who titled the drawing "Tip 'em Up Terry". In early September 1944, Spencer led a section of four pilots on an armed reconnaissance over Belgium where they encountered two of the Luftwaffe's highest-scoring aces,
Emil "Bully" Lang, the Commanding Officer of II/JG26 (173 victories), and Alfred Gross (52 victories), in FW190s over Tirlemont. Although one of his section was killed, the two aces were shot down, Lang killed and Gross so seriously wounded that he did not return to service before the end of the war. In November, Spencer led No. 41 Squadron's advance party to
Diest, arriving in Belgium almost a month ahead of the rest of the unit. He then returned to RAF Lympne to brief the Squadron on conditions at their first continental base of the war. Promoted to squadron leader, Spencer was posted to No. 350 (Belgian) Squadron on 4 January 1945. On 26 February, he was hit by flak in the Rheine-Lingen area of Germany and captured. Just over a month later, when the camp's main gate was left open, he escaped by bicycle, and subsequently motorcycle, with another ex-No. 41 Squadron pilot, Squadron Leader K. F. "Jimmy" Thiele, in a Steve-McQueen-style getaway, in which the pair made it back to Allied lines. Rejoining No. 350 Squadron, Spencer resumed command between 2 and 19 April 1945. On this latter date, he was shot down, this time by rocket fire while strafing a
trawler in
Wismar Bay. He succeeded in baling out and deploying his parachute at a height of just , which he miraculously survived, only to be captured again. The successful jump has since been credited by the
Guinness Book of Records as having been the lowest authenticated survived bail-out on record. Spencer was injured and hospitalised, but liberated by advancing Allied armies approximately two weeks later. Spencer was awarded an immediate
Distinguished Flying Cross (DFC) for his exploits and, in 1947, was also awarded the
Territorial Efficiency Medal and the Belgian
Croix de Guerre with Palm. The citation for his DFC on 22 June 1945 read:
Combat Record ==Photographic career==