'Wilfred' was a British minelaying operation in the Norwegian Leads (8/9 April 1940).

The operation had been mooted as early as September 1939 as a means of preventing German coastal shipping sailing to the south in Norwegian territorial waters with high-grade iron ore shifted by rail from the Luleå region of Sweden, whose Baltic coast was ice-bound in the winter months, to the Norwegian port of Narvik, which was ice-free even in the winter. The Allies wished to prevent the iron traffic to Germany as a high priority, but felt that the implementation of 'Wilfred' might force the Norwegians into the German camp or require the landing of Allied ground forces in Norway to prevent the Norwegians from sweeping the minefields. The latter would be an admirable casus belli for the Germans to intervene in Norway.

The British finally decided to implement 'Wilfred' on 7/8 April, with three fully publicised minefields to be laid in Norwegian waters and with ground forces prepared for rapid delivery to Norway should the situation demand it.

After their 3 September declaration of war in Germany, the UK and France had instituted a naval blockade to weaken Germany by depriving her of the vital imports she needed to sustain her war effort. One of the most crucial imports was iron ore, the basic material of steel, and the primary source of this raw materiel was Sweden, a neutral country. During the winter months the iron ore was moved by rail to Narvik, the ice-free port in northern Norway, for onward movement by sea through Norwegian territorial waters to Germany. Winston Churchill, the First Lord of the Admiralty, was intent on restricting Germany’s ability to wage a modern war, and to pursue this aim developed a plan to mine the Norwegian Leads, the sheltered sea lanes inside the rocky islands off Norway’s west coast which the German ships used to transport the ore. By doing this, Churchill hoped to force the ore ships out into the open sea where blockading warships could sink or capture them.

The UK and France were also anxious to prevent any German seizure of Scandinavia, which would greatly reduce the effectiveness of the blockade and also secure German access to all the iron ore it needed. Such a move would also provide the Germans with many more ports with shorter access to the North Atlantic, and also air bases from which they could fly bombing and reconnaissance missions over the UK.

To prevent this, the two Allies considered their own benevolent occupation of the two neutral countries, but the plan eventually came to nothing. By a time late in March 1940, the plan to mine the Norwegian waters, which Churchill had been urging his colleagues to authorise but which for a variety of reasons had still not been carried out, had become linked with a separate 'Royal Marine' plan to float naval mines downstream along the Rhine river to destroy German bridges and shipping. The British saw 'Royal Marine' as a way of striking back for the heavy damage and loss of life the Germans had inflicted on them by the use of the magnetic mine, but the French initially vetoed the plan, fearful it would bring a wider German retaliation against them.

On 3 April the British began to receive reports of heavy concentrations of shipping and troops in several of Germany’s Baltic ports such as Rostock, Stettin and Swinemünde. It was assumed that this was part of a force that would be sent to counter any Allied move against Scandinavia, so on the same day the British decided to proceed with the mining of the iron ore route as an undertaking entirely separate from 'Royal Marine', and set 8 April as the date on which this 'Wilfred' undertaking would be implemented. Appreciating that 'Wilfred' would almost certainly provoke a major German response, notwithstanding the preparations already underway in their Baltic ports, the parallel 'R4' plan was ordered to prevent German landings by sending strong British and French forces to occupy the key Norwegian ports of Narvik, Stavanger, Bergen and Trondheim before advancing overland to the Swedish frontier and taking control of the iron ore mining sites.

On 3 April the British heavy cruisers Berwick, York and Devonshire, together with the light cruiser Glasgow, reached Rosyth on the Firth of Forth to embark units of the Royal Lincolnshire Regiment for delivery to Norway as part of 'R4' if deemed necessary. More troops embarked on transport ships in the Clyde, and additional forces were held in readiness until indications of German intentions justified sending them to Norway.

On 5 April a large force of warships, escorted by the battle-cruiser Renown of Vice Admiral W. J. Whitworth’s Battle-Cruiser Squadron, and the light cruiser Birmingham, and comprising elements of 'Wilfred' and 'R4', departed the main naval base of Admiral Sir Charles Forbes’s Home Fleet at Scapa Flow in the Orkney islands group and shaped course for the Norwegian coast.

The British plan involved the laying of two minefields. The first of these was 'WV' above the Arctic Circle just to the south of the Lofoten islands in the mouth of the Vestfjord, which leads directly to the port of Narvik at which the iron ore was loaded. The second was 'WS' about three-quarters of the way down Norway’s west coast immediately adjacent the port of Stadlandet. There as also to be a diversionary operation to simulate the laying of the 'WB' minefield just off the Bud headland to the south of the city of Kristiansund.

On 7 April the British force divided, one element to carry on to Narvik and the other to carry out the operations farther to the south.

Force 'WV' bound for the mouth of the Vestfjord comprised the battle-cruiser Renown, the minelaying destroyers Esk, Icarus, Impulsive and Ivanhoe, the destroyers Glowworm and Greyhound, and the escort destroyers Hardy, Havock, Hotspur and Hunter of Captain B. A. Warburton-Lee’s 2^nd Destroyer Flotilla.

Force 'WB' bound for the Bud headland comprised the light cruiser Birmingham and the minelaying destroyers Hero and Hyperion which had initially been part of Renown's escort screen. Force 'WS' bound for the area off Stadlandet comprised the 5,087-ton auxiliary minelayer Teviot Bank and the minelaying destroyers Ilex, Imogen, Inglefield and Isis.

In the event only one minefield was laid. As Force 'WS' steamed toward its destination on 7 April, German ships were sighted in the Heligoland Bight on passage to Norway and the minelaying off Stadlandet was cancelled. Early 8 April, the day designated for the mining operation, the UK informed the Norway of her intention to lay the mines inside Norwegian territorial waters. Soon after this, Force 'WB' carried out its simulated laying of a minefield off the Bud headland using oil drums, and carried out a patrol of the area to 'warn' shipping of the danger.

Force 'WV' in the north duly carried out its task and laid its minefield in the mouth of the Vestfjord. At 05.15 the Allies broadcast a statement to the world justifying their action and defining the minefield areas. The Norwegian government issued a strong protest and demanded the immediate removal of the mines, but by this time the German naval forces were already advancing up the Norwegian coast and from that point onward events moved so quickly that the issue of the minefields became largely irrelevant.

Later in the day, however, the 5,177-ton iron ore transport Rio de Janeiro, heading out from Stettin, was sunk Lillesand in the Skagerrak by the Polish submarine Orzeł. The ship was carrying troops, horses and tanks up the corridor for the German invasion of Norway as part of the Gruppe II attack on Bergen in the 'Bremen' sub-component of 'Weserübung'. About half of the 300 men on board were drowned, and the survivors told the crews of the Norwegian fishing boats which rescued them that they were on their way to Bergen to save it from the British.

A few hours later two German other ships were sunk in the same area: these were Posidonia laden with 8,000 tons of fuel for the U-boats which were to be based at Stavanger, and Krete.

'Wilfred' was now essentially complete and the ships of Force 'WS' and Force 'WB' rejoined the Home Fleet to undertake screening duties, military support and convoy defence as part of the general British 'Rupert' response to 'Weserübung'.

Force 'WV' immediately became embroiled in the early actions of the British attempt to thwart the German landings. The destroyer Glowworm, which had detached from Force 'WV' on 6 April to search for a man lost overboard, encountered the German heavy cruiser Admiral Hipper, and carried out a torpedo attack. After receiving return fire and heavy damage, the destroyer rammed the heavy cruiser, inflicting damage that took a year to repair, and sank soon after this with the loss of 111 men. Diverted to assist Glowworm, the battle-cruiser Renown was in action with the German battle-cruisers Scharnhorst and Gneisenau some 80 miles (130 km) to the west of the Lofoten islands group. Although damage was inflicted by each sides, the two modern German ships failed to take their opportunity to sink the older and slower British battle-cruiser.

Despite learning of these actions and receiving indications from other sources, the Norwegians were still caught largely unprepared for the impending German invasion, which started on the next day with German landings of troops in the main Norwegian ports, from south to north, of Oslo, Kristiansand, Stavanger, Bergen, Trondheim and Narvik. On the same day the destroyer Icarus sank the ore carrier Europa, another German merchant vessel being used to transport men and equipment to Norway, and the 2^nd Destroyer Flotilla later fought with other British naval units in the 1^st Battle of Narvik, sinking several German warships.