The German ‘pocket battleship’ or heavy cruiser the Deutschland had been renamed the Lutzow by Hitler, fearing the symbolic meaning that losing a ship called the Deutschland might have. A year earlier she had been torpedoed by the submarine HMS Spearfish.
The movement of the Lutzow to sea had been discovered as a result of an Enigma decrypt. Following this intelligence Blenheim aircraft were despatched to locate the Lutzow more precisely. They were instructed not to reveal themselves if at all possible, so as not compromise the torpedo planes to follow. Sergeant Pilot T. N. Staples. describes how the ship was found just after midnight on the 12th:
My navigator, with his sea-going experience, was convinced that the battleship and its escort would not be found in the coastal shipping lane just a few miles offshore but was more likely to be sailing in open waters further out to sea. I respected his judgment, and we began our search flying parallel to the coast about 25n.m. out to sea.
We flew this south-easterly course until we had almost reached the end of our patrol line, and I was beginning to wonder if we had done right in being so far out to sea when I saw ahead of me a float plane heading towards the land. I should have connected it with the presence of the enemy ships but I did not and my initial reaction was to attack it. Bearing in mind the purpose of our reconnaissance, this would have been a mistake; but given a few moments to think about it, I am sure I would have reached that conclusion and would have turned to fly back up the coast to continue the search closer inshore.
By a stroke of good fortune, combined with my navigator’s good judgement, the situation resolved itself before I had time to think any more about the float plane. Ahead, and slightly to starboard, the pocket battleship and its escort of five destroyers – two either side and one ahead – suddenly came into view, with fighters overhead. The ships were not much more than a mile away. As I turned away to port I entered the low cloud for concealment and alerted my wireless operator/air gunner to the job ahead of transmitting our sighting report. To do this he had to lower himself from his turret to operate his set in the fuselage to the rear of his position and wind out a trailing aerial!
His full account is at pewteraircraft.
The way was now open for Loveitt’s successful torpedo attack in a Beaufort [see comment below] at 2.18am on the 13th:
Following the sighting by a Coastal Command Blenheim, at about midnight on the 12th, of enemy naval units off the coast of Norway, twenty aircraft of the same Command were despatched to attack this force, which consisted of one pocket battleship (possibly the Lutzow) and five destroyers with air escort.
One aircraft scored a hit with a torpedo amidships on the battleship, and a second aircraft claimed a hit, though the result of its attack was not seen owing to the smoke which surrounded the target.
The enemy force was subsequently shadowed by other aircraft until, on the afternoon of the following day, it was reported approximately 35 miles north-west of the Skaw (Skagerrak). One Beaufort was lost in these operations. The battleship was protected on its retreat by Me. 110′s sent from North-West Germany for the purpose.
From the Air Situation Report for the week see TNA CAB 66/17/9.
Although the Situation Reports were Secret and only circulated at the highest levels, they still concealed some matters -the aircraft had simply been spotted at sea – there was no mention of the Enigma decrypt.