Operation Journeyman

Operation Journeyman was a Royal Navy operation in which a naval taskforce was sent to the Falkland Islands in November 1977 to prevent an Argentine invasion.

The operation was ordered by James Callaghan after fifty Argentine "scientists" landed on Southern Thule prompting fears of an Argentine invasion of the Falklands. The Argentinians set up a military base on Thule. It is likely the prompt action prevented a more serious attack. The force planned under heavy security was led by the nuclear submarine Dreadnought and also consisted of two frigates, Alacrity and Phoebe, and the auxiliaries Resource and Olwen as support vessels. The Argentines rapidly became aware of the taskforce's presence but their forces remained on Thule and Callaghan decided against the use of force to evict them.

The foreign secretary at the time David Owen later claimed that if Margaret Thatcher's government had taken similarly quick action five years later, the Argentinians would not have invaded in 1982 leading to the Falklands War.

Rules of Engagement
The 1977 rules of engagement were: "Commanding officers and aircraft captains are to respond to any aggression with tactful firmness and are to exhibit a determination to meet any escalation, though not to exceed that already carried out by the enemy.

"All use of force must be governed by the principle of using only the minimum force necessary to achieve the aim." Such force must be used only until it was evident "that the immediate aim is being achieved, and must in no way be retaliatory".

The submarine commander was told: "If you are attacked with [anti-submarine] weapons by [Argentine] forces, you are to surface or withdraw at high speed submerged, whichever will be of least risk to life."

They also set up a 50-mile security zone and any ships entering would be told that they must identify themselves and state their plans. Classified documents relating to Operation Journeyman were released in 2005.