Tait was active on bombing operations with 51 Squadron in 1940, including several long-distance raids on Berlin and the first British air raid on Italy, crossing the Alps to bomb Turin, and was awarded the Distinguished Flying Cross (DFC).
 He was promoted to flight lieutenant on 1 February 1940.
By the end of the year, he was commanding 51 Squadron.
On 10 February 1941, he led the aircraft involved in Operation Colossus flying from Malta to drop paratroops in southern Italy.
For this mission, he was awarded the DSO.
 He was given a temporary promotion to squadron leader on 1 March 1941, which was later made substantive with the same seniority.

After Colossus, Tait joined 35 Squadron, the first squadron to be equipped with Handley Page Halifaxes.
 He was awarded the first bar to his DSO for his exploits in leading a daylight raid on Kiel on 30 June 1941.
 He was mentioned in despatches in September 1941.
 Tait was rested from operations and posted to a training unit, but managed nevertheless to fly on the three "Thousand Bomber Raids" in early 1942.

In mid-1942, Tait was appointed to command No.
78 Squadron RAF and was mentioned in despatches during his period in command.
He was made a temporary wing commander on 1 June 1942.
In March 1944, he became base operations commander at RAF Waddington where he continued to fly missions with RAAF Lancaster crews despite holding a non-flying job.
 He was given a substantive promotion to wing commander on 1 March 1944.

He returned to operational duties in May 1944, becoming Master Bomber of 5 Group.
 His service in this role resulted in his being awarded a second bar to his DSO.

He succeeded Leonard Cheshire as commander of No.
617 Squadron RAF in July 1944.
617 Squadron, the famous "Dambusters" squadron, specialised in low-level target marking and precision attacks.
 Under his command, the squadron bombed a series of V-1 storage sites and V-2 launching sites using Barnes Wallis's "Tallboy" 12,000 lb earthquake bomb.
 Tait was awarded a bar to his DFC for pressing home a low-level attack in a daylight raid on the Kembs Dam in southern Germany against fierce defensive fire despite having a damaged aircraft.

On 15 September 1944, Tait led a force of 37 Avro Lancaster bombers of 617 Squadron and 9 Squadron on Operation Paravane.
 Flying from an airfield at Yagodnik, near Arkhangelsk on the Kola Peninsula in northern Russia, they attacked the German battleship Tirpitz, in the Kaa Fjord.
 Despite smoke obscuring the target, the Tirpitz was so severely damaged the German High Command decided the ship could not be restored to seaworthiness.
Tirpitz was therefore moved to Tromsø so its armament could be used as defensive artillery against an anticipated Allied invasion.
The Germans were able to keep the ship's lack of seaworthiness a secret and so its destruction remained a high priority.
Tait led his force in a second attack on 28 October named Operation Obviate, this time from RAF Lossiemouth in Scotland (the ship's move having brought her within range).
This raid was unsuccessful because of the heavy cloud obscuring the target shortly before the bombers arrived.
On 12 November, Tait led his force against the Tirpitz for a third and final raid, Operation Catechism.
 The Luftwaffe failed to intercept the British bombers, and three direct hits by "Tallboy" bombs left the ship capsized west of Tromsø, in the bay of Håkøybotn.

In mid-December 1944, Tait, having completed 101 missions, was grounded and assigned to train Canadian bomber crews.
Like his predecessor at No.
617 Squadron, he was recommended for the Victoria Cross for his "sustained gallantry" over almost five years of operations.
However, unlike Cheshire, he was awarded the third bar to his DSO.
The citation for this award, published in a supplement to the London Gazette in January 1945, reads:
This officer has displayed conspicuous bravery and extreme devotion to duty in the face of the enemy constantly exemplified over a long period of operational flying.
He has completed a very large number of sorties, many of them against most
Tait was active on bombing operations with 51 Squadron in 1940, including several long-distance raids on Berlin and the first British air raid on Italy, crossing the Alps to bomb Turin, and was awarded the Distinguished Flying Cross (DFC).  He was promoted to flight lieutenant on 1 February 1940. By the end of the year, he was commanding 51 Squadron. On 10 February 1941, he led the aircraft involved in Operation Colossus flying from Malta to drop paratroops in southern Italy. For this mission, he was awarded the DSO.  He was given a temporary promotion to squadron leader on 1 March 1941, which was later made substantive with the same seniority.
After Colossus, Tait joined 35 Squadron, the first squadron to be equipped with Handley Page Halifaxes.  He was awarded the first bar to his DSO for his exploits in leading a daylight raid on Kiel on 30 June 1941.  He was mentioned in despatches in September 1941.  Tait was rested from operations and posted to a training unit, but managed nevertheless to fly on the three "Thousand Bomber Raids" in early 1942.
In mid-1942, Tait was appointed to command No. 78 Squadron RAF and was mentioned in despatches during his period in command. He was made a temporary wing commander on 1 June 1942. In March 1944, he became base operations commander at RAF Waddington where he continued to fly missions with RAAF Lancaster crews despite holding a non-flying job.  He was given a substantive promotion to wing commander on 1 March 1944.
He returned to operational duties in May 1944, becoming Master Bomber of 5 Group.  His service in this role resulted in his being awarded a second bar to his DSO.
He succeeded Leonard Cheshire as commander of No. 617 Squadron RAF in July 1944. 617 Squadron, the famous "Dambusters" squadron, specialised in low-level target marking and precision attacks.  Under his command, the squadron bombed a series of V-1 storage sites and V-2 launching sites using Barnes Wallis's "Tallboy" 12,000 lb earthquake bomb.  Tait was awarded a bar to his DFC for pressing home a low-level attack in a daylight raid on the Kembs Dam in southern Germany against fierce defensive fire despite having a damaged aircraft.
On 15 September 1944, Tait led a force of 37 Avro Lancaster bombers of 617 Squadron and 9 Squadron on Operation Paravane.  Flying from an airfield at Yagodnik, near Arkhangelsk on the Kola Peninsula in northern Russia, they attacked the German battleship Tirpitz, in the Kaa Fjord.  Despite smoke obscuring the target, the Tirpitz was so severely damaged the German High Command decided the ship could not be restored to seaworthiness. Tirpitz was therefore moved to Tromsø so its armament could be used as defensive artillery against an anticipated Allied invasion. The Germans were able to keep the ship's lack of seaworthiness a secret and so its destruction remained a high priority. Tait led his force in a second attack on 28 October named Operation Obviate, this time from RAF Lossiemouth in Scotland (the ship's move having brought her within range). This raid was unsuccessful because of the heavy cloud obscuring the target shortly before the bombers arrived. On 12 November, Tait led his force against the Tirpitz for a third and final raid, Operation Catechism.  The Luftwaffe failed to intercept the British bombers, and three direct hits by "Tallboy" bombs left the ship capsized west of Tromsø, in the bay of Håkøybotn.
In mid-December 1944, Tait, having completed 101 missions, was grounded and assigned to train Canadian bomber crews. Like his predecessor at No. 617 Squadron, he was recommended for the Victoria Cross for his "sustained gallantry" over almost five years of operations. However, unlike Cheshire, he was awarded the third bar to his DSO. The citation for this award, published in a supplement to the London Gazette in January 1945, reads:
This officer has displayed conspicuous bravery and extreme devotion to duty in the face of the enemy constantly exemplified over a long period of operational flying. He has completed a very large number of sorties, many of them against most
James Brian Tait