Gibraltar border Spain
Tourists walk to enter the British colony of Gibraltar at its border with Spain, in La Linea de la Concepcion, southern SpainREUTERS/Jon Nazca

The Rock of Gibraltar became the latest EU referendum battle ground and fought over by both sides of the referendum debate, with the Remain camp warning that the British territory may be lost to Spain in a sentiment echoed by Spain's foreign minister. However, the Leave camp has said any such suggestion was scare-mongering and that the EU was more of a threat to Gibraltar than Spain would ever be.

Foreign secretary Philip Hammond made the warning during his first official visit to the territory, when he appeared alongside Gibraltar's chief minister Fabian Picardo.

Hammond said: "I genuinely believe that the threat of leaving the European Union is as big a threat to Gibraltar's future security and Gibraltar's future sovereignty as the more traditional threats that we routinely talk about."

Hammond's warning was echoed by Picardo, also in the Remain camp, who added: "Something upon which those who advocate Brexit should reflect is that they don't just say in Spain that our rights in Europe would come to an end... but also that if we want to continue to have access to European Union rights we would have to consider the concept of joint sovereignty, which would be back on the table."

Spain's foreign minister, Jose Manuel Garcia-Margallo,appeared to raise fears further when he said he hoped Britain would remain in the EU but that if the country did leave Spain would seek to take back the territory immediately.

Speaking on Radio Nacional, he said: "It's true that this gives us an opportunity to have an even more important role than the one we already have with the United States, and don't forget about one other thing: we'll be talking about Gibraltar the very next day."

However Ukip's Julia Reid - MEP for South West Counties and Gibraltar - said: "Gibraltar has nothing to fear, any move for the outpost, which is as British and Britain itself, would be repealed, as every attempt has been for hundreds of years. And even if Britain votes to leave the EU, it doesn't make any difference, Gibraltar will still be British territory and that's that. It sounds more like an old communique from Buenos Aires, rather than a new one from Madrid."

All Gibraltarians will be entitled to vote on the EU referendum on 23 June. Most commentators and analysts believe that they will vote overwhelmingly in favour of remaining within the EU.