The
invasion of Iceland (codenamed
Operation Fork) by the
Royal Navy and
Royal Marines occurred on
10 May 1940, during
WW2. The invasion took place because the British government feared that
Iceland would be used by the Germans, who had recently
overrun Denmark, which was in
personal union with Iceland and which had previously been largely responsible for Iceland's foreign policy. The
Government of Iceland issued a protest, charging that its neutrality had been "flagrantly violated" and "its independence infringed".
At the start of the war, the UK imposed strict export controls on Icelandic goods, preventing profitable shipments to Germany, as part of its naval blockade. The UK offered assistance to Iceland, seeking co-operation "as a belligerent and an ally", but the Icelandic government refused and reaffirmed its neutrality. The German diplomatic presence in Iceland, along with the island's strategic importance, alarmed the UK government.
After failing to persuade the Icelandic government to join the
Allies, the UK invaded on the morning of 10 May 1940. The initial force of 746 Royal Marines commanded by Colonel
Robert Sturges disembarked at the capital Reykjavík. Meeting no resistance, the troops moved quickly to disable communication networks, secure strategic locations, and arrest German citizens. Requisitioning local transport, the troops moved to
Hvalfjörður,
Kaldaðarnes,
Sandskeið, and
Akranes to secure potential landing areas against the possibility of a German counterattack.
The
GIUK gap is an area in the northern Atlantic Ocean that forms a
naval choke point. Its name is an
acronym for
Greenland, Iceland, and the United Kingdom, the gap being the open ocean between these three landmasses. The term is typically used in relation to military topics. The area has been considered strategically important since the beginning of the 20th century.
The GIUK gap is particularly important to the
Royal Navy, as any attempt by northern European forces to break into the open Atlantic would have to be made either through the heavily defended
English Channel, one of the world's busiest seaways, or through one of the exits on either side of Iceland. As the British also control the strategic port of
Gibraltar at the entrance to the
Mediterranean, this means Spain, France, and Portugal are the only Continental European countries that possess direct access to the Atlantic Ocean that cannot easily be blocked at a choke point by the Royal Navy.
From the start of
WW2 in 1939, German ships used the gap to break out from their bases in northern Germany (and from
occupied Norway after April 1940) with a view to attacking Allied shipping
convoys, but
Allied blocking efforts in the North Sea and in the GIUK gap impeded such break-outs. British forces
occupied the Faroe Islands in
April 1940, and
Iceland in May 1940; the
United States took over effective control of Greenland in
1940. But the German
Kriegsmarine profited greatly from the
fall of France in
June 1940, after which
German submarines could operate from
bases on the French coast. Between 1940 and 1942, the
Denmark Strait between Iceland and Greenland remained one of the few areas that
RAF patrol bombers could not reach, and thus became the centre for considerable action.
The origin of the term "gap" dates to this period, when there was a
gap in air coverage known as the
Mid-Atlantic gap or the
"Greenland air gap". This gap was an area that land-based aircraft could not reach and where, as a result, they could not carry out their
anti-submarine duties. The air-surveillance gap eventually
closed in 1943, when longer-ranged versions of aircraft such as the
Short Sunderland and
B-24 Liberator came into service.
