The following work is an eye-opening insight into some peak Cold War contingency planning: how to defend Gibraltar – gateway to the Mediterranean and critical British military hub since 1713. Whilst (like all such plans) it may seem utterly far-fetched, the threat – however small – was real.

The latest in an increasingly hefty and impressive portfolio of work focusing on declassified archive material, veteran Wavell Room author and Thin Pinstriped Line blog titan "Sir Humphrey" sets out the very real measures taken to defend 'The Rock'. Regular readers will enjoy the delightful (and oftentimes farcical) similarities with UK defence matters across the decades… Editor.

Simmering Tensions

In the early hours of May 1982, following indications that a Spanish amphibious force, ostensibly on exercise, had begun sailing closer to Gibraltar, the Governor exercised powers to sortie armed Royal Navy warships, and deploy the Army onto the streets of the rock, to defend it from potential Spanish invasion. This sounds like the plot of a poor Cold War thriller but nearly happened for real. This article is about how in the 1980s the UK actively planned to defend Gibraltar from both Soviet and Spanish aggression in the most unlikely of circumstances.

In 1982 the UK and Spain had strained relations over the issue of Gibraltar since the Spanish closed the land border in 1969. Throughout the 1970s there was genuine concern that Spain could attempt some kind of military operation, leading to elaborate plans being developed to defend 'the Rock' against attack for long enough for cooler heads to prevail. The invasion of the Falklands by Argentina was a particular concern, given the vital military role played by UK military facilities in Gibraltar supporting the Task Force.

In April 1982 the Service Chiefs urgently reviewed plans and capabilities were needed to keep Gibraltar safe, both from Argentine attack and to deter the Spanish from taking advantage of a distracted UK both in the short and medium term. The plans to reinforce the Rock were known as Joint Tactical Plan (JTP) 52 existed to reinforce against the risk of Spanish aggression, but as the Chiefs noted "the plans concerns reinforcement of Gibraltar to meet a direct threat to the Rock, not a contingency plan for a war with Spain. Naturally should events escalate to such an unfortunate level, appropriate forces would be assigned as the situation dictated"!

There was an immediate concern about the presence of a Spanish amphibious force, with 4000 marines embarked operating barely 35 miles from the colony from 26 April to 4 May. While the threat was seen as extremely unlikely, it could not be ruled out. To reduce this risk two RAF Jaguar ground attack jets and an RN Lynx helicopter were dispatched to provide a level of anti-ship capability against Spanish vessels that posed a risk to the Rock.

The CINC in Gibraltar was sufficiently concerned about the risk from this exercise, however unlikely it may have been, to formally put in place "covert preparations to deal with any attempt, admittedly extremely unlikely, at an amphibious assault on Gibraltar".

These measures included covertly preparing and arming Royal Navy warships to be ready to sail at short notice to monitor the force if it moved eastwards out of the exercise area towards Gibraltar. If it continued, then the Army units would be brought to very high readiness, and aircrew in their cockpits. The proposed ROE stated that the Royal Navy would not engage until "enemy opens fire or have landed in Gibraltar and opened fire".

Spain did not, of course, invade, but it led to an urgent MOD reappraisal of the defences needed for Gibraltar to defend against "the situation in which a local Spanish commander might decide to attempt an unsupported and unauthorised adventure against the Rock". The conclusions were that there was insufficient anti-aircraft artillery, relying on WW2 40mm bofors guns to defend the airfield, insufficient counter bat...