Theron joined the South African Permanent Force and attended the Military College 1939 - 1940. He received his wings on 25 April 1940.

On 13 May 1940 he was posted to 1 SAAF Squadron. This unit took part in the East African campaign, initially using Gloster Gladiators.

On 20 September Major Schalk van Schalkwyk with Second Lieutenants Theron and Andrew Duncan strafed Tessenei airfield. A Ca.133 was reported damaged on the ground.

On an early patrol on 4 November over Metema three Gladiators from 1 SAAF Squadron were attacked from above by four CR.42s from 412^a Squadriglia. The South Africans swiftly turned the tables, Lieutenant Theron shooting down one from which the pilot baled out, while Captain Brian Boyle and Lieutenant Andrew Duncan claimed two more (Duncan’s was not confirmed). The Italian pilots claimed to have shot down one Gladiator and reported the loss only of the aircraft shot down by Theron.

In December 1940 1 SAAF Squadron started to receive Hurricanes, which the unit operated together with the Gladiators until all of these aircraft was replaced in the end of February 1941.

At 13:00 on 16 December Lieutenants Theron and Servaas de K. Viljoen and Second Lieutenant Jarvis scrambled from Azaza to intercept bombers. One CR.42 was seen, but it saw them early enough, outdistancing their pursuit in a dive.

On the morning on 27 January 1941, six Hurricanes and six Gladiators of 1 SAAF Squadron, using Sabderat as an advanced landing ground for refuelling, attacked Gura airfield during the day, many aircraft being seen there. While Major Wilmot, Lieutenant Theron and a third pilot remained above as top cover, the other nine strafed, claiming hits on nine S.79s, seven S.81s and three Ca.133s.
The Gladiators taking part in the strafe were led by Captain Brian Boyle (Gladiator N5815) and the other five pilots were Lieutenants Servaas de K. Viljoen, Robin Pare, Andrew Duncan, John Coetzer and Taylor. Hurricane pilots included Major Wilmot, Captain K. W. Driver, Lieutenant John Hewitson and Lieutenant Theron.
It seems that the attack was contested since Tenente Luciano Cacciavillani (attached to 412^a Squadriglia) reported in his logbook that he scrambled at 12:35 and fought against a couple of Hurricanes, with no results.
After the strafe at Gura, Captain Driver and Lieutenant Hewitson continued to Adi Ugri where Driver strafed four more S.81s, claiming damaged to two of them. Hewitson meanwhile strafed other ground target.
The Italians reported that three S.79s and four S.81 were substantially damaged.

At 14:00 on 29 January, 1 SAAF Squadron took off to attack Gura, with six Hurricanes (Major Lawrence Wilmot, Captain K. W. Driver, Lieutenants John Hewitson, Andrew Duncan, Hendrik Johannes Piet Burger and Theron) flying as top cover to five Gladiators, which would strafe. As they approached the Hurricanes run into several S.79s and a large number of CR.42s, which were seen over the airfield, the bombers having just returned from a raid over the front, and the fighters having scrambled at the approach of the South African aircraft. Captain Driver at once attacked an S.79 as it was going in to land, and shot it down in flames, two members of the crew baling out. The Gladiators then arrived, led by Captain Brian Boyle. These also met the Fiats, Lieutenant H. P. Smith (Gladiator N5851) and Lieutenant E. A. Jarvis each claiming one shot down.
Capitano Antonio Raffi, commander of the 412^a Squadriglia, was above with two of his pilots, Tenente Luciano Cacciavillani and Maresciallo Aroldo Soffritti (they scrambled at 15:20), and he saw the Hurricane shoot down the S.79 before he could intervene. He then spotted the Gladiators, which he believed to be six strong, and at once, a great dogfight begun, during which the South Africans saw many Fiats falling away. Driver meanwhile had seen Adi Ugri landing ground on which four S.81s were dispersed, and attacking these, he left one (claimed as a S.79) in flames.
On return to base the combat with the Fiats was fully discussed, and it was decided that five had been shot down, one each by Lieutenant Smith and Lieutenant Jarvis, the other three being impossible to allocate to individual pilots. All the SAAF aircraft returned safely, although one Gladiator (N5831) had been hit by a single bullet.
This proves how easy it was to overestimate the damage caused, and indeed the numbers involved, in a whirling dogfight. Although several CR.42s were hit and damaged, none was in fact shot down. Tenente Cacciavillani's CR.42 was badly damaged by 50 hits, and Maresciallo Soffritti's was also damaged. Capitano Raffi’s own aircraft was hit five times and he recorded that he took ten bullets in his parachute and lost the fabric in the fuselage close to the cockpit and the tail plane. It seems that Raffi’s fire hit and damaged Lieutenant Smith Gladiator, who landed unhurt. The Italians reported combat against four Hurricanes and six Gladiators and reported one Gladiator shot down. Tenente Cacciavillani fired 60 rounds of 7.7mm, and claimed a Gladiator probably destroyed (shared) (strangely enough, this claim has been cancelled by a pen line in his logbook).

At 14:30 on 19 February, five Hurricanes (Captain Kenneth Driver, Lieutenants John Coetzer, Theron, Johan van der Merwe and W. J. A. White) from 1 SAAF Squadron took off to escort four Wellesleys attacking Asmara again. The Hurricanes claimed one destroyed CR.42 by strafing.

At 12:30 on 20 February, Lieutenants Robin Pare, John Coetzer, Theron and Dirk C. Uys took off to attack Massawa aerodrome (and Decamere and Adi Ugri?). They found and damaged four CR.42s and a Ca.133.
It seems that in fact four CR.42s, two Ca.133 and two S.81s were damaged in this raid.

Air reconnaissance had reported that new CR.42s being assembled at Massawa after delivery by transport aircraft, and at 08:00 on 21 February, Major Lawrence Wilmot from 1 SAAF Squadron took off from Kassala with Captain Brian Boyle and Lieutenants Robin Pare, John Coetzer, Theron, Servaas de K. Viljoen and E. A. Jarvis. The Hurricanes refuelled en route at Agordat and took off at 11:00, attacking Massawa an hour later. A small number of aircraft was seen outside the hangars, but the number inside was not known, so all six hangars were attacked, the pilots approaching at zero feet and firing directly into them; all were left in flames, the roof of one being blown right off by Major Wilmot. Six Ca.133s and a CR.42 were strafed in the open, and claimed in flames, while Lieutenant Robin Pare wiped out an anti-aircraft position and crew, which were firing on Major Wilmot. His guns then jammed but he continued to make dummy runs on the AA posts, being the last to leave the area. Lieutenant Coetzer was however shot down and killed by AA fire, his Hurricane (V7658) was seen crashing in flames.
In fact, three Ca.133s and two S.81s, all of which had been damaged the previous day, were destroyed, and one more of each was damaged.

On 23 February 1941, seven Hurricanes of 1 SAAF Squadron flew forward to Tole where they refueled. At noon, Major Lawrence Wilmot (V7733?) led Captain Brian Boyle and Lieutenant Andrew Duncan to strafe Makele airfield while Captain K. W. Driver, Lieutenant Servaas de K. Viljoen, Lieutenant E. A. Jarvis and Lieutenant Theron provided top cover to the Vickers Wellesley acting as the navigation leader and which was intended to distract the Italians from the three low-flying Hurricanes as they went in. However, the RAF bomber lost its way soon after take-off, being dutifully followed by the top cover formation. In the target area, Major Wilmot realised that something was wrong when he saw a rising dust cloud to his left. He led his two companions toward this.
Finding Makele, the trio went in to strafe. Major Wilmot set fire to a CR.32, which was on the ground with its pilot Sottotenente Vincenzo Forcheri of the 410^a Squadriglia in the cockpit, about to take off. He leapt out under fire and managed to reach a trench.
Without their top cover, the Hurricanes were vulnerable to surprise attack, and at that moment reportedly three CR.32s arrived (the dust had been the sign of their scramble). Two fled but Sottotenente Alberto Veronese made good use of their advantageous position and dived on Major Wilmot’s aircraft, shooting it down. Lieutenant Duncan was on him like a flash and shot him down in flames. Veronese managed to parachute to safety, slightly wounded.
Wilmot had in the meantime carried out a crash-landing after that his Hurricane had been hit in the radiator, and became a POW.
Captain Driver, leading the four top-cover Hurricanes, now saw smoke rising, and dived down to join the strafing, the formation claiming five S.79s and three CR.32s set on fire and three S.79s as damaged.

In the morning on 22 March two Hurricanes of 1 SAAF squadron escorted six Wellesleys and six Blenheims to Asmara, but south of the town three 412^a Squadriglia CR.42s were seen, one of which at one disappeared. Lieutenant Theron attacked the leading fighter and his fire killed the pilot, the aircraft crashing in flames 20 miles south-east of the town. A second CR.42 was claimed by Lieutenant J. B. White, also reportedly seen to crash.

He left the squadron in April 1941 and was posted to 7 SAAF Squadron in 1942.

On 6 August 1942 12 of 7 SAAF Squadron’s fighters, with six more aircraft from 6 Squadron undertook a strafing attack during which his Hurricane was hit by Flak, obliging him to crash land and become a PoW.

He spent the rest of the war in Stalag Luft III in Germany.

Theron ended the war with 1 biplane victory and a total of 2.

Claims:

Kill no.	Date	Time	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1940
1	04/11/40		1	CR.42 (a)	Destroyed	Gladiator II		Metema	1 SAAF Squadron
	1941
	19/02/41	14:30-	1/5	CR.42 (b)	Shared destroyed on the ground	Hurricane		Asmara	1 SAAF Squadron
	20/02/41		1/4	CR.42 (c)	Shared destroyed on the ground	Hurricane		Massawa	1 SAAF Squadron
	20/02/41		1/4	CR.42 (c)	Shared destroyed on the ground	Hurricane		Massawa	1 SAAF Squadron
	20/02/41		1/4	CR.42 (c)	Shared destroyed on the ground	Hurricane		Massawa	1 SAAF Squadron
	20/02/41		1/4	CR.42 (c)	Shared destroyed on the ground	Hurricane		Massawa	1 SAAF Squadron
	20/02/41		1/4	Ca.133 (c)	Shared destroyed on the ground	Hurricane		Massawa	1 SAAF Squadron
	21/02/41	12:00-	1/7	Ca.133 (d)	Shared destroyed on the ground	Hurricane		Massawa	1 SAAF Squadron
	21/02/41	12:00-	1/7	Ca.133 (d)	Shared destroyed on the ground	Hurricane		Massawa	1 SAAF Squadron
	21/02/41	12:00-	1/7	Ca.133 (d)	Shared destroyed on the ground	Hurricane		Massawa	1 SAAF Squadron
	21/02/41	12:00-	1/7	Ca.133 (d)	Shared destroyed on the ground	Hurricane		Massawa	1 SAAF Squadron
	21/02/41	12:00-	1/7	Ca.133 (d)	Shared destroyed on the ground	Hurricane		Massawa	1 SAAF Squadron
	21/02/41	12:00-	1/7	Ca.133 (d)	Shared destroyed on the ground	Hurricane		Massawa	1 SAAF Squadron
	21/02/41	12:00-	1/7	CR.42 (d)	Shared destroyed on the ground	Hurricane		Massawa	1 SAAF Squadron
	23/02/41	p.m.	1/4	S.79	Shared destroyed on the ground	Hurricane		Makele airfield	1 SAAF Squadron
	23/02/41	p.m.	1/4	S.79	Shared destroyed on the ground	Hurricane		Makele airfield	1 SAAF Squadron
	23/02/41	p.m.	1/4	S.79	Shared destroyed on the ground	Hurricane		Makele airfield	1 SAAF Squadron
	23/02/41	p.m.	1/4	S.79	Shared destroyed on the ground	Hurricane		Makele airfield	1 SAAF Squadron
	23/02/41	p.m.	1/4	S.79	Shared destroyed on the ground	Hurricane		Makele airfield	1 SAAF Squadron
	23/02/41	p.m.	1/4	CR.32	Shared destroyed on the ground	Hurricane		Makele airfield	1 SAAF Squadron
	23/02/41	p.m.	1/4	CR.32	Shared destroyed on the ground	Hurricane		Makele airfield	1 SAAF Squadron
	23/02/41	p.m.	1/4	CR.32	Shared destroyed on the ground	Hurricane		Makele airfield	1 SAAF Squadron
	23/02/41	p.m.	1/4	S.79	Shared damaged on the ground	Hurricane		Makele airfield	1 SAAF Squadron
	23/02/41	p.m.	1/4	S.79	Shared damaged on the ground	Hurricane		Makele airfield	1 SAAF Squadron
	23/02/41	p.m.	1/4	S.79	Shared damaged on the ground	Hurricane		Makele airfield	1 SAAF Squadron
2	22/03/41		1	CR.42 (e)	Destroyed	Hurricane		20m SE Asmara	1 SAAF Squadron

Biplane victories: 1 destroyed.
TOTAL: 2 destroyed, 21 shared destroyed on the ground, 3 shared damaged on the ground.
(a) Claimed in combat with CR.42s from 412^a Squadriglia, which lost one aircraft while claiming a Gladiator. 1 SAAF Squadron claimed three Fiats without losses (of which two were confirmed).
(b) Totally during the day it seems that one CR.42, one S.79 and two Ca.133s were burned on the ground against claims by 1 SAAF Squadron on three S.79s, three CR.42s and two Ca.133s.
(c) Four CR.42s, two Ca.133 and two S.81s damaged on the ground.
(d) Three Ca.133s and two S.81s, all of which had been damaged the previous day, were destroyed, and one more of each was damaged.
(e) Claimed in combat with CR.42s from 412^a Squadriglia.

Sources:
Luciano Cacciavillani's personal logbook and photo courtesy of Cacciavillani family (Luciano jr and Alberto)
Dust Clouds in the Middle East - Christopher Shores, 1996 Grub Street, London, ISBN 1-898697-37-X
Gloster Gladiator Home Page - Alexander Crawford.
Springbok Fighter Victory: East Africa Volume 1 1940 – 1941 – Michael Shoeman, 2002 African Aviation Series No. 11, Freeworld Publications CC, ISBN 0-958-4388-5-4
Those Other Eagles – Christopher Shores, 2004 Grub Street, London, ISBN 1-904010-88-1
Additional info kindly provided by Stefano Lazzaro, Michele Palermo and Ludovico Slongo.