George Allison edits the UK Defence Journal and spoke out after Spain’s far-right Vox party demanded their country “liberate” the Rock from British “colonial rule”. Mr Allison says that despite claiming sovereignty for decades, the Spanish would have to overcome “impossible” odds to win any military conflict.
The cyber security expert said that despite the UK only having around 300 troops stationed on Gibraltar permanently, its terrain makes it difficult to conquer.
This is coupled with the fact that Spain would need to amass a “considerable” military force on its frontier unnoticed before any attack.
And the threat posed by Royal Navy submarines would mean that Spanish warships would probably play a minimal role in any conflict, he claimed.
He explained: “There are a large network of tunnels under the Rock of Gibraltar, many of them owned by the Ministry of Defence.
“Any attempt to invade the territory would have to contend with British forces embedded in the tunnel, drawing out any operation against the territory significantly.
“This would lead to a ‘guerrilla’ style conflict with Spain in Gibraltar that would see Spanish forces take heavy casualties and take many months.
“Whilst this is happening, the United Kingdom would be sending support to the territory from the air and sea.
“Spain would have to move quickly so it could catch British forces off guard and stop them fortifying the tunnel network.
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Much of the initial reaction force would consist of thousands of elite soldiers from the Parachute Regiment, he said.
He continued: “I have no doubt that Spain wouldn’t be able to take or hold Gibraltar, not least because of the protracted fighting but also because it would create a significant period of political turmoil for the country.
“Spain couldn’t afford a sustained conflict with Britain militarily, diplomatically or economically.
“The key to making any sort of headway for Spain would be a surprise.
“But building up a large force would ultimately alert the British and make any sort of effort against the territory by the Spanish impossible.”
Mr Allison spoke after Vox called on the Spanish government to demand Gibraltar’s “immediate liberation and reincorporation to the national territory”.
The right-wing politicians are also demanding Spain oppose “any agreement with the Government of the United Kingdom that does not address the labour rights of the workers of Campo de Gibraltar and the elimination of the money laundering, tax evasion and smuggling networks present in the Rock after years of inaction by the Spanish authorities”.
It referred to the Rock as a “colony”, and continued: “The central government is asked to implement a specific recovery plan for Campo de Gibraltar, which has as a priority an effective re-industrialisation that allows the economic and social recovery of the area, deteriorated by the abandonment of administrations and unfair competition from the British colony.”
Express.co.uk previously reported how Gibraltar’s most prominent Brexiteer said closing the Rock’s frontier would be “500 times” more damaging for Spain.