The row between Ireland and Scotland over fishing rights around Rockall has deepened, with Irish skippers saying that they have no intention of leaving the disputed waters.

The Scottish government has threatened to take action against Irish vessels, which it says are fishing illegally around Rockall.

The rocky outcrop lies around 230 nautical miles northwest of Donegal and 240 miles west of Scotland.

The chief executive of the local fishermen’s co-op in Greencastle, Co Donegal, the closest Irish port to Rockall, has said the skippers intend to stay fishing where they have worked for 30 years.

"Since yesterday, the Scottish government has told us that there is an exclusion zone of 12 miles around Rockall. So our boats are inside that at the moment and they are going to continue fishing there", said John D O’Kane of Greencastle Fishermen’s Co-Operative.

He spoke by phone to Adrian McCleneghan, one of three Irish skippers currently in the Rockall area.

During the conversation the vessel owner said "we are working about seven miles from Rockall at the moment ... there are four or five Scottish boats in close proximity but there is no sign of any Navy boats for the moment anyway."

The UK claims sovereignty over the uninhabited islet, however the Irish Government does not recognise its claim over the territory.

Speaking to RTÉ News, Mr O'Kane accused the Scottish authorities of bringing in a rule that is against the law of the sea, against EU law and has no legal standing whatsoever.

He said hopefully this can be sorted out at political and government level because fishermen from Greencastle and other Irish ports have been working in the area around Rockall for 30 years.

Asked how might the row might escalate, Mr O’Kane said if a Scottish naval vessel arrests one of the Irish boats, it will probably be brought to a port somewhere on the west coast of Scotland, a court case will follow, with a possible fine for the boat owners. He said that one of the big problems would be the down time in fishing.

He described the Scottish government's action as "a political stunt" by the SNP who are in favour of staying in Europe, but have very little support from Scottish coastal communities and are now looking to improve their standing with them.

He said the Irish Government must fight this challenge "tooth and nail".

Politicians representing fishing communities in Donegal have said the escalating row could have serious implications.

Fianna Fáil TD for Donegal Pat 'The Cope' Gallagher said the news was unexpected.

The Leas Ceann Comhairle of the Dáil said he could not understand why Scotland was now taking what he described as illegal action.

He said he believed there were four Irish vessels currently in the Rockall area.

"I believe they have no right to prevent our vessels from carrying out legitimate opportunities off Rockall and we have been doing that for years," he told RTÉ News.

"Neither has the United Nations Convention on the Law of the Sea recognised this or indeed the European Common Fisheries Policy.

"I believe it is now time for the Irish Government to immediately enter into discussions with [the UK government] with a view to resolving this very volatile situation."

Sinn Féin TD Pearse Doherty said the Scottish intervention was deeply unhelpful.

He said: "This is a serious intervention that could threaten the livelihood of our fisher community. It could lead to boats being impounded, nets being impounded and other materials.

"It needs to be resolved and we’re calling on the Government to escalate diplomatic conversations with the Scottish authorities and with the British authorities."

A Scottish Government spokesperson said: "Irish vessels or any non-UK vessels for that matter have never been allowed to fish in this way in the UK's territorial sea around Rockall and, despite undertaking extensive discussions with the Irish authorities on the matter, it is disappointing that this activity continues.

"There has actually been an increase in that illegal activity and, with the Rockall fishery season nearly upon us, it is our duty and obligation to defend the interests of Scottish fisheries and ensure compliance with well-established international law.

"We have provided an opportunity for the Irish Government to warn their fishers not to fish illegally and hope that this opportunity is taken up as this will of course obviate the need to take enforcement action - which would otherwise be implemented to protect our fisheries interests."

The head of Scotland's biggest fishing industry organisation has told the BBC that it backed the Scottish government’s intervention.

Bertie Armstrong from the Scottish Fishermen's Federation said Ireland would be "unwise" to pick a fight over fishing rights in Scottish waters.

He said Ireland had "mumbled and complained in the past" about the UK's claim over Rockall but had never legally challenged it.

He said this should have been done if the Irish Government "felt so strongly" about the issue. He said the British claim over the territory had been clearly established under international law.

Mr Armstrong said Ireland had never made any counter claims over the territory, and he therefore "dismissed" the Irish complaints as "irrelevant".

He said the Scottish government was doing "exactly the right thing" and was "entirely right" to take whatever action was appropriate to stop the "illegal activity" engaged in by Irish vessels fishing at Rockall.

He said he hoped a patrol vessel from Scottish government compliance would investigate whether this activity was ongoing, and he hoped they would make arrests if necessary.

Mr Armstrong said monitoring systems had the ability to tell how many fishing vessels were currently in operation in the area.

Boats from a number of Irish ports in Greencastle, Killybegs, Rossaveal, Castletownbere and Clogherhead fish for species including haddock and squid in the waters off Rockall.

May to October is the busiest time of the year, but some vessels work there from February on. 

There is no tradition of Northern Ireland boats from the three main centres in Co Down travelling to the Rockall area.