During the Allied 'push' in September 1918 the squadron concentrated on tactical bombing from Clairmarais, making a particularly intense and successful effort on two nights at the end of the month. Then, in driving rain with a cloud base of 1,000 ft (305 m), it bombed the roads in front of the Ypres salient, dropping 12 tons in two nights and firing the nose guns of the 'Fees' at every light seen. Some crews flew up to nine sorties each night.
The squadron then returned to strategic bombing in the Germans' rear until World War 1 was over. It then became part of the Army of Occupation (the only F.E. squadron to do so), remaining at Bickendorf until March 1919. The squadron then moved across to Tallaght in Ireland before disbanding on 1 August 1919.
On 12 April 1937 B Flight of No. 99 Squadron, at Mildenhall, equipped with Handley Page Heyfords, was expanded to squadron strength and given No.149's number plate. This was during the rushed expansion of the RAF to be ready for the war that was clearly imminent. Before World War 2 broke out the squadron had re-equipped with Vickers Wellington Mk Is, and was operational on 4 September 1939, flying a raid on warships at Brunsbuttel. It was soon found that the Wellington was unsuitable for daylight raids, and there was little for No.149 to do for the rest of the 'phoney war' apart from 'Nickel' leaflet raids over Germany at night.
It was when the German offensive in the Low Countries began in May 1940 that the squadron began the bombing offensive against Germany which occupied it for the rest of the war. The Wellington was soon found to be the best of the British bombers, 50 No.149 and the other No.3 Group squadrons were busily involved, at first in tactical bombing to try to halt the German advance on the British troops evacuating from Dunkirk, then against the invasion barges massing at the Channel ports. But the squadron was really meant for strategic bombing and it was this task, principally against the Ruhr, on which No.149 concentrated during the winter of 1940-1. During the long winter nights it was able to fly farther afield, and included Berlin and the industries of northern Italy in its targets. All through 1941 it soldiered on with the Wellington Mk IC, flying whenever required, weather permitting. In November the squadron began to convert to the Short Stirling four-engine bomber without ceasing operations, bringing the Stirling onto operations on 26 November.
Mildenhall and No. 149 had seemed inseparable, but in April 1942 the squadron moved over the fields to Lakenheath, the new satellite airfield still being completed. From here it continued the night offensive for the next two years, using its Stirlings to carry a heavy bombload each night against the Reich. At this time it was the fashion in the four-engine bomber squadrons to have a conversion flight to bring crews from the OTUs up to scratch on the Stirling before going on operations. On 30 May 1942, the squadron participated in the first of the 'thousand bomber' raids, on Cologne, putting up 17 aircraft together with four from its conversion flight, a maximum effort indeed. The long and dangerous routine of night raids against Germany continued all through 1942 with Stirling Mk Is.
On 28 November the target for the squadron was the Fiat works at Turin, which involved a flight over the Alps. Flight-Sergeant R.H. Middleton was flying Stirling BF372 (OJ:H) when, in the low-level attack, he was hit and badly wounded, losing his right eye. Other members of the crew were also wounded. Despite desperate wounds the two pilots flew the aircraft all the way back to the English coast, where Middleton kept the aircraft flying until most of the crew had baled out successfully; Middleton was lost when the aircraft crashed into the sea, but for his bravery he was awarded the VC.
The following year, 1943, was to be similar to 1942. In February more powerful Stirling Mk IIIs began to replace the Mk Is, but the problem with the type was its low ceiling and the squadron was used increasingly on mining sorties as the heavily defended land targets were unhealthy places for low-flying bombers at around 15,000 ft (4572 m).
1944 came and the squadron was still flying operationally with Stirlings, but by the early summer it had moved to Methwold where it soon re-equipped with the Avro Lancaster. This enabled the squadron to put in greater efforts in the final stages of the Battle of Germany, and its aircraft remained on the offensive all through the autumn and winter of 1944-5 and right up to the end of the war in Europe.
The squadron was retained in the peacetime Bomber Command, first at Tuddenham, then at Stradishall and finally back to Mildenhall, where it re-equipped with Avro Lincolns in 1949. These it began to use on 'Sunray' flights to Shallufa in Egypt, where it co-operated with the Canal Zone squadrons in exercises. But the Lincoins lasted with the squadron only until 1 March 1950, when it was disbanded at Mildenhall.
This was for a purpose, however, for on 14 August of that year No.149 reformed at Marham and was given Boeing Washington B.Mk 1s. These it took to Coningsby in October to form part of the second wing of these B-29 bombers, on loan to the RAF. The crews enjoyed the luxury of the internal appointments and the improved bombsight, and flew the type in all Bomber Command's exercises and competitions for the next three years.
Then the squadron re-equipped with English Electric Canberra B.Mk 2s and, having mastered jet bombing, went to Germany in August 1954, the first Canberra squadron based there. It formed the spearhead of RAF Germany's strike force there until 31 August 1956, when No.149 was disbanded at Gutersloh.