The GIUK gap (Greenland, Iceland, and the United Kingdom, Gap) is a bottleneck between the North Atlantic and North Sea. It can be used by the UK, Iceland, Greenland and/or Ireland to blockade Scandinavian and N.W. Russia and loss of condole of it would allow those nations to send vessel out of the North Sea in to the North Atlantic unopposed. This fact was noted in WW1, WW2 and the Cold War. British fighter jets, navel fighter jets and some time navel vessels would patrol between the North Cape of Norway and Iceland as a general security measure from the early 1960s to the mid 1990s.