Between Rockall and a hard plaice: Fishing rights are at the centre of a post-Brexit fight for maritime territory.

Glasgow, Scotland – A rocky outcrop in the North Atlantic may appear an unlikely flashpoint in international relations, but in recent weeks, this uninhabitable lump of granite has become the scene of a Scottish-Irish tug-of-war.

Rockall is an island which covers about half the area of an ice-hockey rink, sitting 260 miles (418km) west of Scotland’s Western Isles. It was thrust into the headlines earlier this month when the Scottish Government warned that vessels from the Republic of Ireland could be boarded if they fish within 12 miles (19km) of the rock formation.

The United Kingdom claims ownership over Rockall and the 12 nautical miles of ocean around it – and the Scottish government says it has always been unlawful for any non-British boats to fish within this radius.

The Irish, including its national government, disputes Scotland’s legal claim. They say their vessels have been fishing within the waters of this eroded volcano – which is rich in squid, monkfish and haddock, and carries the prospect of undiscovered oil and gas reserves – for generations, and will continue to do so.

“We’ve had boats fishing in Rockall for the past 30 years,” says John O’Kane, from Greencastle Fishermen’s Co-Operative, of County Donegal, Ireland. “So, [the Scottish stance] was a shock – and came out of the blue as far as we were concerned.”

Scottish industry experts have given their backing to the Scottish government’s position over Rockall, which was claimed by the UK in 1955 and incorporated into Scotland’s territory 17 years later.

Greenpeace activists occupied the territorially disputed Rockall in 1997 in protest at exploration for oil [Reuters]

“From my point of view it’s nationally recognised as being in the jurisdiction of UK waters,” Jimmy Buchan, chief executive officer of the Scottish Seafood Association, told Al Jazeera.

Scotland claims the Irish government first raised the issue of fishing rights around Rockall a year after the UK’s 2016 Brexit referendum to leave the European Union.

But Irish Prime Minister Leo Varadkar told his parliament earlier this month: “Rockall is a rock, essentially a sea stack in the middle of the ocean. It’s uninhabitable, uninhabited and I don’t think it is something that Ireland and Scotland should fight over. We don’t have a claim on it. We don’t accept any other sovereign claim on it.”

That said, as Brexit rumbles on towards some kind of conclusion, Buchan suggests that politics is at play: “This is maybe the EU muscling in on an opportunity, should Brexit happen, and [doing so] through the Irish angle… There may be rich minerals out there – in oil and gas – which other nations would see as quite lucrative.”

Indeed, amid the Scottish-Irish dispute, Iceland also fired its own shot across the bows of the Rockall standoff. Last week, the small Nordic island reaffirmed its national claim by declaring that “the Hatton-Rockall area is part of the Icelandic continental shelf”.

Today, Scotland, as a constituent nation of the UK, as well as Ireland, Iceland and Denmark – on behalf of the Faroe Islands – all claim rights over the seabed around this rocky outcrop.

As Scottish and Irish officials attempt to resolve the spat, O’Kane claims that, under EU law, vessels from Ireland are perfectly entitled to fish around Rockall. However, he does concede that the island is likely to feature in post-Brexit negotiations between Britain and the EU.

And he says the dispute surrounding Rockall could be just the tip of the iceberg for Irish fishing rights come Britain’s departure from Europe.

“If there was a hard Brexit or a no-deal Brexit, it would be ninety-nine percent sure that we would be put out of UK waters immediately,” O’Kane says to Al Jazeera. “And that is not a scenario that anyone in the Republic of Ireland wants at all.”