Disputed Status of Gibraltar - The Isthmus

The Isthmus

The territory of Gibraltar contains an 800-metre (2,625 ft) section of the isthmus that links The Rock with mainland Spain. Although it is argued by Spain that the isthmus was never ceded by Spain; rather, it was gradually occupied de facto by Gibraltar, the fact is that there was a stretch of land labelled as neutral territory separating Spain from Gibraltar.

The growth of Gibraltar onto the isthmus began with the construction of two forts in the northernmost part of the ceded territory. In 1815, Gibraltar suffered a yellow fever epidemic. This led to a Spanish concession so a temporary health camp could be built on the isthmus. After the plague was over, Gibraltar did not remove the camp. In 1854, a new epidemic prompted more health camps, gaining Gibraltar another 800 meters. The occupation of the isthmus culminated in 1938 with the construction of the airport during the Spanish civil war.

The Treaty of Utrecht does not specify the extent of British sovereignty over Gibraltar beyond the fortified perimeter of the town as it was in 1704. However as the Treaty ceded the town "together with the port, fortifications, and forts thereunto belonging" and there were several such forts along the line of the current frontier, it can be inferred that this area was indeed also ceded. The United Kingdom further claims that its title to the southern part of the isthmus is based on continuous possession over a long period (Prescription (sovereignty transfer)).

It should be noted that large parts of the neutral territory were also taken over by Spain over time. A prime example is the Spanish town of La Linea de la Concepcion, which was also built on the said neutral territory with the sole purpose of curtailing the natural growth of Gibraltar as a city.