I compiled this from a website called British Army Medical Services and the Malta Garrison 1799-1979. If there are any errors it was because the website was difficult to follow.
The Built Up of the Royal Artillery and Royal Malta Artillery in Malta 1939-43
September 1939
At the outbreak of war the artillery defences of Malta consisted of:
- one anti-tank regiment (26 RA), with 4 batteries
- one heavy anti-aircraft regiment (7 RA), with 3 batteries (2 British and one Maltese)
- 2 coast artillery regiments (4 RA and 1 RMA) with 6 batteries between them (3 British and 3 Maltese)
That is a total of 13 batteries (9 British and 4 Maltese) under 4 regimental headquarters.
According to the source I am using the roles of the Coast Artillery were: Counter Bombardment; Close Defence; and the Examination Anchorage Service. The counter bombardment role was performed by 4 Heavy Regiment, RA (later renamed 4 Coast Regiment) with seven 9.2-inch guns. The other roles were performed by 1 Heavy Regiment, RMA (later renamed 1 Coast Regiment) with ten 6-inch and nine twin 18-pdrs
26 Anti-Tank Regiment, RA had arrived in Malta in April 1939. It supported the Malta Infantry Brigade. According to the source I am using its batteries included: one manning 18-pdr Beach Guns; one battery of 12-pdr guns; one mobile battery of 6-inch howitzers and one battery of 3.7-inch howitzers.
A HAA battery had 8 guns either 3-inch or 3.7 inch so that presumably there were 24 anti-aircraft guns on Malta. Earlier in the year the anti-aircraft requirements of Malta had been set at 112 heavy and 60 light AA guns plus 24 searchlights.
June 1940
Between then and Italy's entry into the war it had grown to one anti-tank, 2 coast artillery and 3 HAA regiments with the formation of 2 RMA and 11 RMA. 8 new batteries had actually been formed, but one HAA Battery was sent to Egypt leaving 3 HAA, 3 LAA and one searchlight unit in Malta. This mean that there was now a grand total of 20 artillery batteries (9 British and 11 Maltese) on Malta consisting of 6 coast (3 British and 3 Maltese), 4 anti-tank (all British) and 10 air defence batteries. The air defence batteries consisted of:
- 6 HAA batteries (2 British and 4 Maltese). At 8 guns per battery the total strength should have been 48 HAA guns, but the British official history says that there were only 34 HAA guns on Malta;
- 3 LAA batteries (all Maltese). At 12 Bofors 40mm guns per battery there should have been 36 LAA guns, but the British official history says that there were only 12 LAA guns on Malta;
- One searchlight battery (8 Battery, RMA). The establishment of a S/L battery was 24 "lights" and this unit was the only air defence unit that was up to full strength because the official history says that there were 24 searchlights on Malta.
End 1940
In September 1940 the 26th Anti-Tank Regiment, RA became the 13th Mobile Coast Defence Regiment. Its 4 anti-tank batteries (15, 40, 48 and 71) were reorganised into 2 defence batteries (15/40 and 48/71).
Although this reduced the number of RA batteries on Malta to 7 it was more than compensated for by the arrival of 8 batteries (4 HAA, one LAA, one searchlight and 2 field) in October and November, which produced a net increase to 15 batteries made up of 6 HAA, one LAA, one searchlight, 3 coast, 2 defence and 2 field units. The number of regimental headquarters increased to 6 (2 HAA, one searchlight, one coast, one mobile coast defence and one searchlight) in November 1940 when 4th Searchlight, 10th HAA and 12th Field Regiments arrived.
Meanwhile 4 new RMA batteries (2 HAA, one LAA and one coast) were formed in the fourth quarter of 1940, bringing the total to 15 (4 coast artillery, 7 HAA, 4 LAA and one searchlight) plus 5 HAA Battery in Egypt. There were still 3 regimental headquarters (1 Coast, 2 HAA and 11 HAA).
Thus the total strength of the artillery on Malta at the end of 1940 was 30 batteries (15 British and 15 Maltese) under 9 regimental headquarters (6 British and 3 Maltese) consisting of:
- 12 heavy anti-aircraft batteries (6 British and 6 Maltese) under 4 HAA regimental headquarters (7 RA, 10 RA, 2 RMA and 11 RMA). If at full strength the 12 batteries would have had a combined strength of 96 guns;
- 5 light anti-aircraft batteries (one British and 4 Maltese) either independent or under one of the HAA regiments. If at full strength the 5 batteries would have had a combined strength of 60 guns;
- 2 searchlight batteries (one British and one Maltese) in one regiment (4 Searchlight, RA/RMA). If at full strength the 2 batteries would have had a combined strength of 48 searchlights;
- 7 coast batteries (3 British and 4 Maltese) in 2 regiments (4 Coast, RA and 1 Coast, RMA);
- 2 mobile coast defence batteries (all British) in one regiment (13th MCD, RA);
- 2 field batteries (all British) in one regiment (12th Field, RA). After the reorganisation of 1938 field batteries would normally had twelve 25pdr gun-howitzers, so there could have been 24 field artillery pieces on the Island.
1941
The expansion of the artillery in Malta led to the formation of HQ 7 AA Brigade in January 1941 and 10 AA Brigade in May 1941. These formations were not disbanded until the second quarter of 1944.
According to the source I am using there seems to have been a HQ Royal Artillery in 1941, with a HQ Fixed Defences under it to control the non-anti-aircraft units and the 2 AA brigades controlling the AA units.
- 12th Field Regiment, RA was reorganised in November 1941, when it was brought up from 2 to 3 batteries.
- 13th MCD Regiment, RA was renamed 26th Defence Regiment on 29th June 1941. The regiment was increased from 2 to 3 batteries when 13th Defence Battery, RMA was formed in August 1941.
- 74th LAA Regiment, RA was formed on Malta in February 1941. Under it was the existing British LAA battery. It was gradually brought up to a strength of 4 batteries during the course of 1941 with batteries that arrived in March, July and August;
- 3rd LAA Regiment, RMA was formed in March 1941 to control the 4 existing Maltese LAA batteries, which had previously been independent or under the HAA regiments;
- 4th HAA Regiment, RA and 32nd LAA Regiment, RA arrived in Malta on 24th July 1941. Each regiment had 3 batteries;
At the end of the year there were 40 batteries on Malta (24 British and 16 Maltese) under 13 regimental headquarters (9 British and 4 Maltese). There were now 14 HAA batteries (8 British and 6 Maltese) with an establishment of 112 guns; and 11 LAA batteries (7 British and 4 Maltese) with an establishment of 132 guns. The searchlight establishment was still 48 "lights".
1942
The Commander Royal Artillery (CRA) controlled all the artillery units in Malta. At the beginning of the year he had 40 batteries under 13 regimental headquarters, which would increase to 46 under 15 regimental headquarters by the middle of the year. This strength would be maintained until the spring of 1943.
The fixed defences were increased from 4 to 5 regiments in June 1942 when 5 Coast Regiment, RMA was formed. There were now 3 coast regiments (4 RA, 1 RMA and 5 RMA), one defence regiment (13 RA) and one field regiment (12 RA). However, the number of batteries was only increased from 13 to 15 consisting of 10 coast (an increase of 3), 2 defence (a decrease of one) and 3 field batteries.
By 1942 there were 5 HAA regiments (4 RA, 7 RA, 10 RA, 2 RMA and 11 RMA) under 10th HAA Brigade. No new regiments were formed, but the number of HAA batteries was increased from 14 to 15 (8 British and 7 Maltese) by the formation of 14 Battery, RMA in January. This was assigned to 4 HAA Regt, RA so that it now had the normal 3 batteries instead of 2. At an establishment of 8 guns per HAA battery there should now have been 120 heavy AA guns on Malta.
By 1942 there were 3 LAA regiments (32 RA, 74th RA and 3 RMA) under 7th LAA Brigade. They were reinforced 3 batteries in January 1941 with the arrival of 32 LAA Regt RA with 2 batteries in January and the formation of 15 Battery, RMA. There were now 14 LAA batteries (9 British and 5 Maltese) on the Island with a total establishment of 168 Bofors 40mm guns.
Finally there was 4th Searchlight Regiment, RA/RMA with 2 batteries (484 Battery, RA and 8 Battery, RMA). There was no change to the searchlight organisation in 1942.