The German battle cruisers Gneisenau and Scharnhorst were reported as having been sighted by an aircraft from H.M.S. Ark Royal during the evening of the 20th in a position 600 miles W.N.W. from Cape Finisterre, steering to the northward. Subsequent shadowing by aircraft was prevented by low visibility.
At 2020 on the 21st an aircraft on patrol reported sighting two battleships or cruisers and one destroyer about 130 miles W.S.W. from Brest, steering east at 20 knots. Naval units sent to intercept this force failed to locate them and further air search was prevented by the weather. …
On the night of the 20th/21st the record number of forty-two aircraft were despatched by Bomber Command to lay mines in the vicinity of Brest, Lorient and St. Nazaire, towards which ports two Scharnhorst-Class Battle Cruisers were believed to be making. Other sea mining operations were carried out at the mouth of the Gironde and in the Fehmarn Channel.
From the Naval Military and Air Situation Report for the week.