'Fuller' was a British contingency plan for naval and air forces to sink any major German warships trying to break to the north-east through the English Channel from Brest to Germany (1941/42).
As soon confirmed by the success of 'Cerberus', the plan was completely inadequate. The various British efforts and perceptions indirectly or directly associated with 'Fuller' were based on the assumptions that the battle-cruisers Scharnhorst and Gneisenau, accompanied by the heavy cruiser Prinz Eugen, would make their dash at night and in cloudy conditions in order to give the ships cover, and thus make it impossible for bombers to operate, and would steam as close as possible to the French coast so that German fighter cover could be called if required.
The factors which decided the nature of the British plan included the use of Air Marshal Sir Arthur Harris’s RAF Bomber Command to bomb and mine the Brest area and the cleared channels on the route along the English Channel on a nightly basis from 11 December 1941; the appreciation of Air Chief Marshal Sir Philip Joubert de la Ferté, commanding RAF Coastal Command, that there were greater numbers of German destroyers and torpedo boats in the Channel than was normal, and that the three German major warships had been observed taking part in exercises together, facts which he included in a memorandum to the Air Ministry indicating his opinion that the German ships would try to breakout through the Channel between 10 and 15 February; the British decision, taken in light of the destruction of the Bismarck at the end of 'Rheinübung', to adopt the tactic of crippling the German squadron with air-launched torpedoes to slow them and thus create the opportunity for surface ships to arrive and sink them; the establishment by Coastal Command of three patrol lines in the form of 'Stopper' east of the Brest peninsula, 'Habo' and 'Line SE'; Coastal Command’s belief that the German effort would be made on 15 February when there would be no moon; and the agreement with this last by the Admiralty as well as RAF Bomber Command and Air Marshal Sir William Sholto Douglas’s RAF Fighter Command.
The only dissenting voice was that of Vice Admiral Sir Bertram Ramsay, commanding in Dover, who believed that a daylight break-out would be attempted, and that the RAF and Royal Navy forces lacked the torpedo bombers necessary to stop the German squadron. Ramsay therefore requested and received the redeployment of the FAA’s No. 825 Squadron, flying Fairey Swordfish biplanes, from Lee-on-Solent to Manston. All Coastal Command’s other torpedo bomber squadrons were in the Mediterranean. So far as surface vessels were concerned, Ramsay had available to him six destroyers notionally but in fact not on four-hour standby in the Thames river estuary, three escort destroyers which were slower than the German ships and lacked torpedo tubes, and thus posed nothing but a nuisance threat to the large German ships, and 32 motor torpedo boats based at Dover and Ramsgate but offset in significance by the German S-boot flotillas.
For a number of reasons aircraft of the FAA, Coastal Command and Bomber Command could not offer an effective level of support. This resulted largely from the fact that all the British services expected the Germans to time their dash through the English Channel so that the three major warships passed through the Strait of Dover at night and would therefore be less vulnerable to the British coastal artillery.
In fact the Germans thought it more important to keep the element of surprise for as long as possible by departing Brest at night unnoticed and thereby not provide the British with the 12-hour warning they would otherwise have been afforded. The significance of the German night departure was compounded by the fact that British nocturnal air reconnaissance failed to spot the movement as a result of radar failures.
Thus the first intimation that the Germans had started 'Cerberus' came from RAF radar stations, which detected unusually high levels of German air activity over the Channel. The ships were then spotted by the pilots of two Supermarine Spitfire fighters, who were under orders to maintain radio silence and thus reported the ships only after they had landed. Fighter Command was not expected to make the first sighting of the German squadron as it headed north-east up the English Channel, and valuable time was lost as the sighting was reported up the chain of command and on to the Royal Navy and Bomber Command.
Unco-ordinated attacks by motor boats and six Swordfish torpedo bombers from Manston then inflicted no significant damage, and all the Swordfish aircraft were lost together with all but five of the 18 crew members. Bomber Command was slow to act, and only 39 out of the 242 bombers which took part found and attacked the ships, but achieved no hits. Some 398 Spitfire and Hawker Hurricane fighters of Fighter Command flew several sorties on 12 February 1942. Altogether, 675 RAF aircraft (398 fighters, 242 bombers and 35 Lockheed Hudson and Bristol Beaufort aircraft of Coastal Command) took off to search for and attack the German ships.
At about 12.00 on 12 February the British coastal artillery started to engage the German warships. The South Foreland battery began to track the ships with its newly installed radar, and 12.19 fired it first salvo. Maximum visibility at the time was 5 miles (8 km), and the fall of shot was not seen either optically or electromagnetically, though the radar clearly revealed the zig-zagging of the ships. The battery fired 33 rounds, all of which missed.
Ramsay’s six destroyers were taken by surprise and, instead of being on station, were on gunnery practice in the North Sea. As soon as they had been alerted, the destroyers steamed to the south to intercept the German squadron, but arrived in time to fire only one salvo of torpedoes, all of which missed. The fire of Gneisenau and Prinz Eugen severely damaged Worcester, which suffered 24 dead and 45 wounded. Several salvoes from Gneisenau destroyed the starboard side of the bridge, and the nos 1 and 2 boiler rooms. Prinz Eugen hit the destroyer four times, setting her on fire.
Thus the British had been unable to prevent the German squadron before they reached the safety of German home waters, and in the process had suffered severe damage to one destroyer and lost 42 aircraft.