When Italy invaded Greece from Albania on 28 October 1940, the Elleniki Vassiliki Aeroporia (Royal Hellenic Air Force) had two Gloster Gladiators on its inventory. The Gladiators had privately been bought in 1938 by a businessman named M. Zarparkis Homogenos from Gloster at a cost of £9200 and then presented to the Air Force. This was done in the same way as the procurement of the Air Force two Avia B.534s in 1936. The Gladiators and Avias were not used operationally at the time.

After the intervention of the Royal Air Force to help Greece, British aircraft started to arrive to country in the beginning of November 1940. The first were eight Blenheim Ifs of 30 Squadron, who arrived on 3 November.

Greece fighters were hard pressed and reinforcements were requested and received in form of ex-RAF Gladiators. On 2 December 1940, eight Gladiators from Sidi Haneish in Egypt were flown over by pilots of 112 Squadron and handed over to the Greek Air Force. The British pilots were then flown back to Egypt in a Bombay. To these aircraft were added six ex-80 Squadron machines and one from 112 Squadron. 21 Mira, who previously had been equipped with PZL P.24s under the command of Sminagos (Captain) Ioanis Kellas, was withdrawn to Eleusis to re-equip. Their remaining serviceable P.24s were distributed between 22 and 23 Mira.

Pilots of 21 Mira at Yanina following their re-equipment late in 1940 with ex-RAF Gladiators.

21 Mira was operational again on 23 December when they arrived to Yanina to replace 80 Squadron.

The unit claimed Greece first Gladiator kill on 8 January 1941 and the last one on 2 April 1941. During the conflict 21 Mira made claims on eight enemy aircraft.

At the time of the German blitzkrieg through the Balkans, 21 Mira were stationed at Paramythia and later moved to Kalambaka/Vassiliki.
When the remaining Greek fighters were moved to Amphiklia/Lodi on 16 April, twenty-one remained - eight Gladiators, 11 PZLs and two Bloch 151s. All of them, except three (unspecified type) were destroyed on a surprise attack by German Bf 109s on 19 April. The three remaining fighters were evacuated to Eleusis were two more were destroyed by a German attack on 20 April by Bf 109Es from II/JG27.

Known Gloster Gladiator claims made by the Greek Air Force.

Claims:

Kill no.	Date	Number	Type	Result	Pilot	Plane type	Serial no.	Locality	Unit
1	08/01/41	1	CR.42 (a)	Destroyed		Gladiator		Kelcyre	21 Mira
2	25/01/41	1/3	BR.20 (b)	Shared destroyed	Ioanis Kellas	Gladiator		Premeti - Kelsyre area	21 Mira
2	25/01/41	1/3	BR.20 (b)	Shared destroyed		Gladiator		Premeti - Kelsyre area	21 Mira
3	09/02/41	1	Enemy fighter (c)	Destroyed	Ioanis Kellas	Gladiator		Kelcyre-Tepelene area	21 Mira
4	09/02/41	1	Enemy fighter (c)	Destroyed	Ioanis Kellas	Gladiator		Kelcyre-Tepelene area	21 Mira
5	09/02/41	1	Enemy fighter (c)	Destroyed	Anastasios Bardivilias	Gladiator		Kelcyre-Tepelene area	21 Mira
6	09/02/41	1	Enemy fighter (c)	Destroyed	Ilias Dimitrakopoulos	Gladiator		Kelcyre-Tepelene area	21 Mira
7	09/02/41	1	Enemy fighter (c)	Destroyed	Nikolaos Kostorizos	Gladiator		Kelcyre-Tepelene area	21 Mira
	10/02/41	1	G.50 (d)	Probable		Gladiator		Premeti area	21 Mira
	10/02/41	1	G.50 (d)	Probable		Gladiator		Premeti area	21 Mira
	10/02/41	1	G.50 (d)	Probable		Gladiator		Premeti area	21 Mira
8	02/04/41	1	Z.1007bis (e)	Destroyed		Gladiator		Ptolemais	21 Mira
9	02/04/41	1	Z.1007bis (e)	Destroyed		Gladiator		Ptolemais	21 Mira
10	15/04/41	1	Ju 87 (f)	Destroyed		Gladiator		Trikala area	21 Mira

TOTAL: 10 destroyed, 3 probably destroyed.
(a) Not confirmed with Italian sources.
(b) Shared between Ioanis Kellas, another 21 Mira Gladiator and a PZL-24 from 22 Mira. Claimed in combat with BR.20s from the 116^a Gruppo, 37^o Stormo B.T. 21 and 22 Mire claimed three bombers. Italian records report two heavily damaged bombers. One forced-landed at Lecce with 3 crew members dead and a second force-landed near Berat.
(c) Claimed in combat with fighters from 24^o and 160^o Gruppi. The 21, 22, 22 Mire claimed eight enemy fighters for the loss of one PZL while several more were damaged. The Italian fighters claimed five PZLs and four Gladiators without loss.
(d) Claimed in combat with G.50bis from 154^o Gruppo C.T. Not confirmed with Italian sources.
(e) Only one Z.1007bis lost. This was a machine from 35^o Stormo from which one member of the crew escaped by parachute.
(f) This claim can’t be verified with Luftwaffe records.

Known Gloster Gladiator losses in aerial combat by the Greek Air Force.

Losses:

Loss no.	Date	Pilot	Plane type	Serial no.	Unit	Result	Shot down by	Locality
1	09/02/41	Hiposminagos Antonis Papaioannou	Gladiator		21 Mira	Damaged beyond repair	Italian fighter (a)	Kakavia
2	11/02/41	Anastasios Bardivilias	Gladiator		21 Mira	Destroyed	CR.42 (b)	Katsika airfield
3	23/02/41	Episminias Constantinos Chrizopoulos	Gladiator		21 Mira	Destroyed	G.50bis (c)	Kelcyre-Devoli
4	15/04/41	Ioanis Kellas	Gladiator		21 Mira	Destroyed	Bf 109 (d)	W Trikkala

TOTAL: 4 lost in aerial combat.
(a) The Greek pilot was seriously wounded in both legs after being shot down by a CR.42 or G.50bis. Italian fighters claimed four Gladiators but only one was lost. One claimed by G.50bis from 24^o Gruppo CT and three claimed by CR.42s from 160^o Gruppo CT (one each by Ten. Edoardo Crainz, Serg. Magg. Luciano Tarantini and Serg. Magg. Aurelio Munich)
(b) Shot down by CR.42s from the 150^o Gruppo CT. The Italian fighters claimed two Gladiators but only one was lost.
(c) Shot down and killed by G.50bis from 154^o Gruppo CT. The Italian fighter claimed one and three probable Gladiators but only one was lost.
(d) 4./JG27 claimed two Gladiators but only one was lost. Ioanis Kellas was slightly wounded in the ensuing crash-landing.

Known ex-RAF Gladiators transferred to 21 Mira.

Source:
Air war for Yugoslavia, Greece and Crete - Christopher Shores, 1987
Luftwaffe Claims Lists - Tony Wood
Royal Air Force Aircraft L1000-N9999 - James J. Halley, 1993 Air-Britain (Historians) Ltd, Kent, ISBN 0-85130-208-4
Additional information kindly provided by Lars Larsson and Dimitrios Vassilopoulos.