The territorial time-share that no-one's talking about

But the national government is not too bothered – Spain will get said territory back again at the end of January.

Pheasant Island – known as La Isla de los Faisanes in Spain, and L'Île des Faisans in French, sits in the Bidasoa river that sits on the border between the two, close to the frontier towns of Irún (Basque Country) and Hendaye on the France side.

Uninhabited and just 5,000 square metres in size – about as big as the plot for a luxury villa with a pool, or an acre-and-a-quarter – Pheasant Island is known as a 'condominium', which is pan-European terminology for jointly-owned land.

Given that it sits equally in France and Spain, rather than fight over it, the two nations have agreed to 'own' it for six months of the year each.

The Spanish government handed the island over to France on August 1, and France will give it back on February 1, 2018 before they swap over again as usual.

La Isla de los Faisanes is thought to be the oldest – and smallest – internationally-owned territory in the world.

And, despite its name, no pheasants are ever known to have lived there.

Authorities in both countries say the island needs little maintenance, and when the river levels are low enough, they can even walk to it to prune the trees and tidy up – something they do roughly three times a fortnight.

Other than an unremarkable milestone declaring that the Pyrénéen Treaty of November 7, in the year 1659, was signed there to put an end to the particularly bloodthirsty Thirty Years' War and to agree to the enclave being neutral and jointly-owned and symbolic of Franco-Spanish cooperation, the island contains nothing but trees and plants.

In the post-Mediaeval years, international prisoners have been handed over the border via the island, and a handful of Royals have said their wedding vows on it.

Otherwise – although it can be seen easily from two countries, being just 50 metres from Spain and the same distance from France – nobody is allowed on it, not even to take a selfie with one leg in either country.

Access is exclusive to the Navy based in San Sebastián between February and July inclusive, and that of Bayonne the rest of the year, to carry out maintenance.

The last time L'Île des Faisans was violently trespassed was by ETA terrorists 43 years ago when they were caught by the Guardia Civil attempting to swim from Spain to France, leading to a scuffle in which a policeman and an ETA member were killed.

It has, however, grown in size – erosion caused by the river meant it dwindled over 200 years to just five metres wide and 80 metres long by the mid-17^th century, but since then, both countries have shored it up and it is now 38 metres wide and 215 metres long.