The exceptional and extremely rare Second World War Fighter Command Scotland June 1943 Commander of the Order of the British Empire, Great War Mesopotamia Voisin Pilot’s Aerial Resupply of Kut 1916 belated Second Award Bar and German East Africa operations 1917 Distinguished Service Cross, India North West Frontier Waziristan 1919-21 Flight Commander, and January 1941 Fighter Command Scotland Mention in Despatches group awarded to Air Commodore W.H. Dunn, C.B.E., D.S.C. and Bar, Royal Air Force, formerly Royal Naval Air Service. Dunn flew operationally as a pilot out in Mesopotamia from late 1915, when he joined Squadron Commander Brownhill’s Squadron, flying in the Short 827 Seaplane. The initial three RNAS seaplanes for Mesopotamia, the pilot of one of one being Dunn, arrived and were attached to the Mesopotamian half-flight, a unit formed from the Australian Flying Corps, and it was as such that Dunn played a most important role during the siege of Kut between early December 1915 through to 29th April 1916. Attempts to relieve Kut were becoming desperate, and on 15th April the RFC / RNAS and AFC were ordered to start dropping food, medical supplies, money, and spare parts for the garrison wireless. Also on one occasion, a 70lb millstone was dropped to grind corn, parachutes being made from old aeroplane fabric and shipped up river from the Basra. After several experiments the designer of the supply drop equipment, was able to build a food dropping attachment for the aircraft which consisted of a long bar fitted to a bomb frame from which the bomb guides and fittings had been removed. The bar was pivoted on one end while at the other end a quick-release mechanism enabled a BE2c to drop two 25lb bags while a further two 50lb bags (one on each wing) could be released by the pilot via a simple slip knot. Each bag was made up of a tight inner and loose outer, which absorbed the impact well. All drops were made from about seven thousand feet. On the first day of food drops, 15th April 1916, 3,350lb of stores were dropped, below the stated requirements that garrison had requested, but considering the machines and pilots available, it was a creditable result. The aircraft and RNAS pilots involved are detailed, and the only RNAS pilot to fly a Voisin on the 15th April was Dunn, who made seven flights in total and dropped 850lb of stores. This was however not without risk, and the German aircraft did their best to interfere, engaging defenceless aircraft which had been stripped of their weapons to facilitate the required supplies. Although over 19,000lb of supplies were dropped in 61 sorties, it was to be to no avail. Despite its apparent failure, this air re-supply was notable, however, as it was the first time in history that aircraft had been used to carry and drop supplies of any significance. During these operations to attempt to relieve Kut, Dunn flew numerous sorties, with seven flights alone being recorded on 15th April. He was be belatedly recognised for his efforts, with the award of a Second Award Bar to his Distinguished Service Cross which was gazetted to him in May 1918, he having in the meantime earned his Distinguished Service Cross, gazetted in February 1918 for operations in German East Africa from November 1916 to December 1917, when he flew Voisin’s on numerous sorties in support of the British advance against Von Lettow’s forces. Dunn had displated gallantry and devotion to duty in carrying out reconnaissances, bombing and photographic flights during the military operations in the Lindi area, when serving as a flight commander with Bowhill’s No.8 RNAS Squadron. Dunn was go on to briefly service in the Adriatic on seaplanes during late 1918, and thew flew as a flight commander in Bristol F2B aircraft with No. % Squadron out in India during the operations against the tribes in Waziristan on the North West Frontier, becoming one of 334 R.A.F. recipients of the India General Service Medal with clasp Waziristan 1919-21. With the Second World War, Dunn further distinguished himself as the Senior Air Staff Officer to the Headquarters of No.14 Fighter Group. This unit oversaw the fighter cover over Scotland, and in this role Dunn would have served through the Battle of Britain. Dunn was awarded a Mention in Despatches in January 1941, and subsequently appointed a Commander of the Military Division of The Most Excellent Order of the British Empire in June 1943. Dunn was ultimately S.A.S.O. with Headquarters for Air Defences Eastern Mediterranean from March 1943, and then saw service with the Advanced Air Defence Headquarters located at Nicosia in Cyprus.
Group of 11: The Most Excellent Order of the British Empire, Commander, C.B.E., 2nd type, Military Division, with full length of neck ribbon; Distinguished Service Cross, GVR GRI Cypher, hallmarks for London with date letter ‘c’ for 1918, with Second Award Bar; 1914-1915 Star; (FLT.S.LT. W.H. DUNN, R.N.A.S.); British War Medal and Victory Medal; (CAPT. W.H. DUNN. R.A.F.); India General Service Medal 1908-1935, 1 Clasp: Waziristan 1921-24; (F./L. W.H. DUNN, R.A.F.); 1939-1945 Star; Africa Star; Defence Medal; War Medal; Jubilee Medal 1935; Coronation Medal 1937. Later eleven are mounted court style for wear / display.
Condition: Good Very Fine.
Sold together with an original photograph of the recipient in RAF dress uniform wearing his miniature medals for his Great War awards, namely DSC and Bar and 1914-1915 trio. Also a large archive of copied documentation including photographs of Dunn on operations in East Africa.
Wilfred Henry Dunn was born on 19th September 1893 at Genoa, Italy, and later lived in Balham, London. Dunn then went forward for a career at sea in the Merchant service and in 1914 qualified as a Third Officer working with the British India Company. With the Great War he received a commission as a probationary Flight Sub Lieutenant into the Royal Naval Air Service on 28th January 1915, and then went forward for pilot training through the Grahame-White School at Hendon, gaining his Aviator’s Certificate (No.1106) and his “wings” on 11th March 1915. Posted to the Royal Naval Air Station at Calshot on 13th March 1915, he was confirmed in the rank of Flight Sub Lieutenant on 22nd May 1915, and is noted as having suffered an engine failure to his Farman Seaplane during a flight on 4th July 1915, and made a force landed on sands at Bembridge on the Isle of Wight, the aircraft being then stranded on the sands there. Shortly afterwards Dunn was posted to the seaplane tender Empress from 8th July 1915. Empress was just completing modification by Cunard at Liverpool with a permanent, four-aircraft, hangar in the rear superstructure and a pair of cranes were mounted at the rear of the hangar to hoist the seaplanes in and out of the water. Empress was transferred afterwards to Ireland to Queenstown for the rest of the year, before moving to the Mediterranean.
Dunn however found himself posted out to Mesopotamia in September 1915, he being a pilot with Force 'D' of the Royal Naval Air Service who were to be employed in operations to attempt to relieve the siege of Kut. Once in Mesopotamia he joined Squadron Commander Brownhill’s Squadron, flying in the Short 827 Seaplane. The initial three seaplanes, the pilot of one of one being Dunn, arrived and were attached to the Mesopotamian half-flight, a unit formed from the Australian Flying Corps. Because the Tigris river was too shallow for the seaplanes to use at that time of year, they were converted into Shorthorns. On 27 September, Kut was captured and the half-flight moved there. In the ’Cross and Cockade Journal' (Summer, 1976, vol17 no2), there is an article titled 'The Indian Flying Corps and the Australian Half-Flight', by Dr. Brian P. Flanagan. The article is based on service reminisces and photographs of a Mr. A. E. Shoreland, a sergeant in the Australian unit, and the log-book of Air Commodore W. H. Dunn. The article gives a good summary account of the air activities during Gen. Townsend's ill-fated campaign, and covers more than the title indicates. A good portion of the account, and of the photographs, relate to an R.N.A.S. detachment, commanded by Squadron Commander Robert Gordon, assigned to support the flotilla of river gunboats the Royal Navy was operating on the Tigris. The initial equipment was three Short 827 float-planes; the unit was detached from RNAS forces assigned to East Africa after the destruction of the Konigsberg. Unfortunately this article is not available to the cataloguer.
British air support had been pathetically inadequate since the start of the campaign, 30 Squadron RFC having few aircraft and these were unsuitable for the hot, dusty conditions. In June 1915 three Short Type 827 seaplanes (Ser. 822, 825 and 827) were sent from UK via Gibraltar and arrived in Basra on 5th September. Under the command of Squadron Commander (Major RMLI) Robert Gordon RNAS, who had been transferred with RNAS air and ground crew from East Africa, the seaplanes were intended to be used for co-operation with the Naval forces in Mesopotamia but forward reconnaissance and communications duties in support of the advancing (and later retreating) British forces were vital. The Type 827 seaplanes also proved under-powered in the conditions and they were converted to wheeled undercarriages for land operations which increased their utility. As Kut fell under siege the RNAS Seaplanes withdrew to Basra on 4th December.
On 17th January 1916 the RNAS squadron was reinforced by the arrival, in SS Chantara, of two Voisin III biplanes (Ser. 8505 and 8506) and the RNAS and RFC aircraft and pilots operated interchangeably from then on as a composite unit, supporting the Army ‘Tigris Corps’ attempting to relieve the besieged and soon starving garrison at Kut. In February more aircraft, transported in SS Hunts Castle, arrived for the RNAS in the shape of two more Voisin IIIs (Ser. V.1540 and V.1541), two Henri Farman F.27 (Ser. 3900 and 3901) and five Short 184 seaplanes (Ser. 8043 to 8047) with more powerful engines. On 6th March the composite RNAS/RFC force was formally constituted as one formation under army orders with Wing Commander Robert Gordon RNAS as ‘Air Commander Tigris Column’. His ‘air force’ was formed of 30 Squadron RFC and the RNAS Squadron under Squadron Commander Frederick W Brownhill RNAS, who had brought the five Short 184s out from England.
As mention the RNAS detachment was based at Basra from 4th December. The siege of Kut officially lasted from 5th December 1915 through to 29th April 1916. By February 1916 the siege was into its second month, and the weather was turning. Becoming very hot and the high sun glare and dust adding to the misery. To top it all, the mosquitoes and flies became unbearable and appeared in plague proportions, maddening horses and men alike. After General Younghusband’s first attempt to break through in January 1916, another was set for 7th March. The Battle of the Dujaila Redoubt was likewise a failure, the British losing over 4,000 men. General Aylmer was subsequently replaced by General Gorringe as Commander of the Tigris Corps, now newly promoted Lieutenant General.
Attempts to relieve Kut were becoming desperate, and on 15th April the Royal Flying Corps were ordered to start dropping food, medical supplies, money (£10,000 in gold, silver and notes) and spare parts for the garrison wireless. Also on one occasion, a 70lb millstone was dropped to grind corn, parachutes being made from old aeroplane fabric and shipped up river from the Basra AP.
After several experiments, Captain E.M. Murray, the designer of the supply drop equipment, was able to build a food dropping attachment for the aircraft which consisted of a long bar fitted to a bomb frame from which the bomb guides and fittings had been removed. The bar was pivoted on one end while at the other end a quick-release mechanism enabled a BE2c to drop two 25lb bags while a further two 50lb bags (one on each wing) could be released by the pilot via a simple slip knot. Each bag was made up of a tight inner and loose outer, which absorbed the impact well. All drops were made from about seven thousand feet, but the BE2cs proved difficult to handle, the Voisins being much better suited and carrying the most food (150lb per trip). The Henry Farman could carry 200lb without an observer. The distance from the landing ground at Ora to Kut was 23.5 miles. It was not just the Kut garrison that was suffering: everyone in 30 Squadron and the attached Australian / RNAS unit was showing the signs of short rations and fever and dysentery were common.
On the first day of food drops, 15th April 1916, 3,350lb of stores were dropped, below the stated requirements that garrison had requested, but considering the machines and pilots available, it was a creditable result. The aircraft and RNAS pilots involved are detailed, and the only RNAS pilot to fly a Voisin (Voisin Serial No.8506) on the 15th April was Dunn, who made seven flights in total and dropped 850lb of stores. Also, 500lb of stores were dropped by RFC machines flown by RNAS pilots who completed 47 food dropped flights all told.
This was however not without risk. On 26th April two aircraft were shot down, the first a Short 184 Seaplane flown by 2nd Lieutenant Cecil Glasson and 2nd Lieutenant Archibald Cecil Thouless who was killed. The other was a BE2C flown by Lieutenant Donal Davidson, who was severely wounded, but escaped. His unarmed aircraft was delivering supplies an had 32 bullet holes plus the right aileron shot away. Although over 19,000lb of supplies were dropped in 61 sorties, it was to be to no avail.
Two days before the RFC casualties, on 24th April the river steamer SS Julnar loaded with 270 tons of food, and a volunteer crew commanded by Lieutenant Humphrey Osbaldstone Brooke Firman, V.C., R.N., tried to break the Turkish blockade. Steaming 25 miles up the Tigris under cover of darkness, the steamer was halted eight and a half miles downstream of Kut, by steel hawsers stretched across the river. Under heavy fire, most of the crew were killed, wounded or captured and Firman was posthumously awarded the Victoria Cross.
On 27th April 1916, one last desparate act took place that would remain in the secret files of the British and India Office for years. Under a flag of truce, Major General Townshend, accompanied by T.E. Lawrence and Aubrey Herbert of the Arab Bureau in Cairo, sailed upstream to negotiate with Khalil, the Turkish Army commander. Their proposal was that instead of unconditional surrender as demanded, they would offer the Turks two million pounds for the parole of the army, plus guns and ammunition. Enver Pasha rejected the offer suggesting instead that Townshend alone would be paroled to India for a payment of one million pounds plus the guns and stores held in Kut. It was an offer rejected by the British and doomed the troops to incarceration.
Despite efforts by Gorringe and Aylmer to mount a land rescue operation, finally they failed due to Turkish entrenchments, lack of river transport and the floods. On 29th April 1916, and almost starving, the garrison surrendered after 146 days. Despite its apparent failure, this air re-supply was notable, however, as it was the first time in history that aircraft had been used to carry and drop supplies of any significance.
During these operations to attempt to relieve Kut, Dunn would have flown numerous sorties, with seven flights alone being recorded on 15th April. During the two weeks of the supply drop operations, in which 9 aircraft made a total of 140 flights and dropped 19,000lb of supplies, his aircraft had its Lewis guns and ammunition removed, but the pilot still had his revolver! A constant worry for the likes of Dunn was the lack of defensive armament, as German aircraft did their best to interfere in the first ever attempt to keep troops supplied by air. This period was not without incident for Dunn. Back on 14th February 1916 he had crashed his Type 827 Seaplane at Orah, some ten miles south of Kut. On 10th April he wrecked one Voisin, and later on 5th May 1916 he would make another landing under telegraph wires, removing the undercarriage in the process. Finally on 15th June 1915 he was involved in an accident in which his aircraft, a Wight Admiralty 840 Type seaplane was damaged but ultimately repaired. Dunn was promoted to Flight Lieutenant on 1st April 1916.
Dunn had been transferred to the books of Alert, the base ship at Basra on 7th April 1916. Dunn was then taken ill on 8th July 1916 and on the 11th July he sailed for Bombay in India aboard the “Elleuga”, arriving at Bombay on 15th July, where he was admitted to the Taj Mahal Hospital.
Dunn’s ‘conspicuous courage’ out in Mesopotamia would initially go unrewarded, however later in 1918 he would be awarded the Second Award Bar to his Distinguished Service Cross for the operations in the attempt to relieve Kut back in 1916. As of 14th May 1916 his commanding officer, Wing Commander Robert Gordon, would write a report on Dunn stating ‘this officer has flown continuously during all operations since February, and has put in an enormous amount of flying under all weather conditions, and the result of all his flights have been unfailingly good.’ He was recommended by Gordon for promotion. In addition his other commanding officer, Squadron Commander Brownhill, would write of Dunn that ‘he did very good work in Mesopotamia’ also recommending him for promotion.
It was not till November 1916 that Dunn returned to operations, this time in East Africa as part of No.8 RNAS Squadron. This squadron had originally left England in early February 1916, and had disembarked at Zanzibar on St. Patrick’s Day. It initially flew operationally during the operations at Tanga and Bagamoyo in August 1916. Early in August 1916 Squadron Commander Bowhill arrived, and it was early in November 1916 that Dunn that first features in accounts of the East African Campaign, when he arrived with Bowhill and Fitzherbert and ten ratings at the airfield at Lindi, which had been taken over, and was now to be made ready for operations against the German forces who were being pushed further inland. This small party brought a number of crated aircraft which were then assembled, and it was on 9th November 1916 that Dunn took the first Voisin (8702) up for a test flight for 10 minutes in calm weather. Further test flights were marred by engine trouble, until it was eventually destroyed in a forced landing on 27th November when, shortly after takeoff, and at 150ft, the engine completely failed, Neither Dunn, nor his passenger, Lieutenant James were injured. Then on 27th November 1916 when flying in Voisin No.8702, both Dunn and James were again involved in a close call when taxiing they turned their aircraft to avoid a hanger, and this upset the balance of the aircraft and its port wing hit the ground, wrecking the aircraft. Dunn appears to have been briefly hospitalised around this time. The next Voisin to be erected from its crate was 8703, which was taken by Dunn on 17th December 1916 from Dar-es-Salaam to Kilwa Kiswani, on the East African coast south of the Rufiji Delta, where No.26 RFC Squadron had recently established an airfield. This entailed an extremely long flight, more than two hours, over some very difficult country. To reduce the risk of aircraft and personnel, the remaining Voisins (8522, 8700, and 8701) were delivered by sea from Dar-es-Salaam to Kilwa Kivinje where they were landed by lighters on Christmas Day 1916 and then assembled on the beach before being flown up to the airfield at Kilwa Kiswani. Some limited flying was done from Kilwa Kiswani early in the New Year but the weather was poor and the rains were now fast approaching. The increasingly waterlogged state of the airfield forced both the RFC and RNAS to store their aircraft. By the end of February 1917, therefore, most personnel had returned to either Dar-es-Salaam or Zanzibar, leaving the dismantled machines to be cared for by small rear party. Operations from Kilwa would not recommence until May 1917 - once the airfield had dried out. Operations however did also occur in seaplanes from the harbour at Lindi from May 1917, flying in support of the advancing columns. Dunn was recommended for promotion by Bowhill on 15th May 1917, and is noted as sick at Lindi on 20th May 1917, and was sent to hospital two days later, but returned to duty on 29th May. Dunn was then promoted to Flight Commander on 30th June 1917.
By the beginning of June, Bowhill had completed the construction of the airfield at Lindi and the first two Voisins were flown in from Kilwa Kiswani. Their initial task was to complete the survey and mapping of the area ahead of the intended advance. The machines proved difficult to control in the climatic conditions while the area around the airfield proved particularly unhealthy, albeit the officers were accommodated at Kitunda, on higher ground. The squadron, under the direct command of Bowhill, worked very closely with Brigadier General O’Grady, commander of Linforce, who was flown a number of times over the Lindi area. During the subsequent fighting the Voisins provided extremely useful intelligence on the enemy’s dispositions and directed naval gunfire on targets of opportunity. By 18th August, the Germans had been pushed back to Nurunja, but the attack faltered in the face of enemy reinforcements and strong entrenchments.
A further advance was undertaken, in September 1917, by both the Kilwa and Lindi forces. With the RFC operating from Kilwa and the RNAS from Linda, air support was available for both columns. After a brief fight, the Germans withdrew from Nurunja, the Voisins tracking the enemy’s movements and, just as importantly, allowing communication between the various independent units. Dunn is noted as having been admitted to the 1st East African Stationary Hospital suffering from dysentery on 19th September 1917. A considerable amount of work was done spotting for the 4 inch gun that accompanied Linforce. Unluckily, on 24th September 1917, one of the Voisins was forced to land in the bush at Tandamuti Hill with engine trouble. The pilot was unhurt but the aircraft was badly damaged, leaving just two machines available. The advance, however, necessitated that the Voisins be moved forward to an advanced base at Mtua, closer to the front. This was successfully completed on 13th October 1917.
With the squadron’s main efforts focussed on the Lindi area, the few pilots left at Zanzibar continued to carry out occasional seaplane patrols of the sea lanes and channels approaching the island. Zanzibar also continued to provide base support and overhaul facilities. After a pause to replenish stores and recover from heavy fighting on 6th November 1917. The Voisins were again employed in reconnaissance and survey work, as well as photographing and bombing enemy positions. The surviving remnants of von Lettow’s forces had escaped over the Ravuma on 25th to 26th November. He would fight on until the Armistice, but the last enemy forces had been cleared from German East Africa. The land campaign effectively over, Bowhill and the RNAS personnel at Mtua were ordered back to Lindi and thence to Zanzibar which they reached on 6th December 1917. In view of the wear and tear suffered by the Voisins, Bowhill was given authority to delete them, rather than recover the machines to Zanzibar or another theatre of war.
On their departure for Zanzibar, General O’Grady provided the following appreciation of the services provided by Wing Commander Bowhill and his flight, which of course included Dunn. ‘The work done by them is deserving of the highest commendation, and has been invaluable to is’. On 27th November 1917, Bowhill received a message from the Senior Naval Officer, HMS Challenger. ‘I would like to take this opportunity, as Senior Naval Officer on the coast and after three years intimate connection with the Royal Naval Air Service, to express my admiration for the manner in which they have carried out all their duties under, at times, extremely difficult circumstances and my great appreciation of their invariable response to any call I have made of them.’
The London Gazette for 22nd February 1918 records honours for several RNAS officers who had served in East Africa. Wing Commander Bowhill was awarded the Distinguished Service Order ‘in recognition of his invaluable services as Commanding Officer of the Royal Naval Air Service, employed in connection with military operations in East Africa. It is due to his experience and unceasing labour that his small unit of the Royal Naval Air Service has been of such assistance to the military operations. He has instilled a high sense of discipline into those under his orders.’ The Distinguished Service Cross was awarded to Flight Commander Dunn, and Flight Lieutenant Rudolph Dawson Delamere - both officers were commended for their gallantry and devotion to duty shown in carrying out reconnaissances, bombing and photographic flights during the military operations in the Lindi area. The Distinguished Service Cross was also awarded to Flight Lieutenant Ernest Edward Deans in recognition of his great skill and bravery in flying machines of an old type and to Lieutenant Evelyn Cecil Walter Fitzherbert, RNVR, in recognition of his performance as an observer during military operations in East Africa.
Bowhill left for England on 9th January 1918, sailing in the Empress of Britain - so ending RNAS operations in the Indian Ocean after almost exactly three years. Whilst at sea on 12th February 1918 he would once again recommend Dunn for promotion. In the meantime, after Bowhill’s departure, a small rear party, under Flight Lieutenants Dunn and Smethurst, had been left to look after the remaining seaplanes which were eventually deleted in-situ, rather than return them to England.
Dunn’s award of the Distinguished Service Cross was published in the London Gazette for 22nd February 1918, with the following citation: ‘In recognition of his services whilst employed in connection with military operations in East Africa. He did splendid work during the operations in the Lindi area, and carried out valuable bombing and reconnaissance flights.’ It was soon after awards that delated recognition for his services in Mesopotamia during the attempt to relieve Kut came through, he being gazetted with the Second Award Bar to the Distinguished Service Cross, one of only 39 such awards to men from the Royal Naval Air Service during the Great War, the award being gazetted on 17th May 1918 in the section of awards ‘for services in Mesopotamia’ with the following citation: ‘For conspicuous courage and skill in carrying out an extraordinary amount of flying, both in sea and land planes. He is invariably cheerful and ready when called on for work.’ In all only 252 Distinguished Service Crosses and 39 Second Award Bars were awarded to the RNAS for the Great War, 96 awards of a bar being made in total to all branches of the naval forces.
Dunn was transferred into the Royal Air Force on its formation on 1st April 1918 in the tank of temporary Captain, and then embarked from East Africa at Zanzibar on 13th April 1918 aboard the ‘City of Bedford’ and disembarked at Suez on 15th May 1918. On 13th July 1918 he was hospitalised with the 17th General Hospital at Rez-el-Tin in Egypt, being discharged from hospital on 12th September 1918. He then embarked for England at Port Said aboard the transport ‘Kaisar-i-Hind’ on 15th October 1918, and then sailed for Italy, where he briefly saw active service with the Headquarters of No.67 Wing based at Taranto through to the end of the war in November 1918, and seeing operations in the Adriatic theatre.
Post war Dunn was granted a Permanent Commission into the Royal Air Force on 1st August 1919 as a Flight Lieutenant and seaplane Captain. Posted out to India, on 5th December 1919 he was posted to the Staff of the Aircraft Park/Depot in India. However with the ongoing operations against the tribes on the North West Frontier, he then found himself once again operational when posted as a flight commander to join No.5 Squadron and flying in Bristol F2B aircraft. Dunn then flew in the Waziristan operations, becoming one of 334 Royal Air Force recipients of the India General Service Medal with clasp Waziristan 1919-21.
On 14th December 1921 Dunn was posted to the RAF School in India, most likely as an instructor, and on 10th October 1924 was posted home as a supernumerary to the RAF Depot. Then on 28th March 1925 he was appointed a Flight Commander with No.16 Squadron and on 11th August 1925 was appointed a Flight Commander with No.4 Squadron, flying in Bristol F2B Mk111A aircraft out of Farnborough. Promoted to Squadron Leader on 1st January 1926, on 28th May 1926 he was on the Staff of the RAF Training Base at Leuchars in Scotland, and then found himself posted to the RAF Staff aboard the aircraft carrier Vindictive from 26th August 1929. Similarly on 20th January 1930 he was posted to the RAF Staff aboard the aircraft carrier Glorious, where he worked under Wing Commander Anthony Rex Arnold, D.S.C., D.F.C, and with a team of four assistants, was responsible for stores, signals, and operations. On 1st September 1933, Dunn was posted as a supernumerary to the RAF Depot. On 8th November 1933 he was placed on the Half Pay List. Promoted to Wing Commander on 1st January 1934, he was then posted to undertake a Flying Boat Pilot’s Course at RAF Calshot, and subsequently attended the Senior Officer’s War Course at the Royal Navy War College.
Dunn was then appointed Officer Commanding of No.230 Squadron on 23rd February 1935, which operated flying boats from the United Kingdom, Egypt and Singapore during this period. Dunn was promoted to Group Captain on 1st July 1938. With the outbreak of the Second World War, Dunn was appointed Officer Commanding RAF Benson in May 1940, and on 23rd September 1940 he was appointed the Senior Air Staff Officer to the Headquarters of No.14 Fighter Group. This unit oversaw the fighter cover over Scotland, and in this role Dunn would have served through the Battle of Britain, being located with HQ at the Drumossie Hotel in Inverness during 1940 to 1941, and at the Raigmore House in Invernerss from 1941 onwards. He held the rank of temporary Air Commodore from 1st December 1940. It was for his work with Fighter Command that Dunn was awarded a Mention in Despatches in the New Years Honours List as published in the London Gazette for 1st January 1941, and subsequently appointed a Commander of the Military Division of The Most Excellent Order of the British Empire in the King’s Birthday Honours List, a published in the London Gazette for 2nd June 1943.
Dunn was then appointed as Air Officer Commanding No.81 Training Group on 29th July 1942, and was ultimately appointed Senior Air Staff Officer with Headquarters for Air Defences Eastern Mediterranean from 17th March 1943, and then saw service with the Advanced Air Defence Headquarters located at Nicosia in Cyprus. This was established as a forwarding co-ordinating authority for offensive air operations in the Aegean and for fighter protection of shipping in the Levant. Dunn was placed in charge of these operations, and was responsible to Air Vice Marshal R.E. Saul, who was stationed in Cairo. Dunn retired from service on 29th June 1944 in the rank of Air Commodore