Clive Symmons, of Trinity College Dublin, said Irish ministers were “incorrect” to assert that the Scottish government had no basis for excluding Irish fishermen from the islet’s waters.

Ireland has no “leg to stand on” in the issue and Scotland was “within its rights” to threaten to enforce them, he said.

Ronán Long, chairman of ocean governance and law of the sea at the World Maritime University, agreed.

Under the UN Convention for the Law of the Sea (Unclos), rocks can generate 12-mile territorial sea limits.

After Scotland warned it would enforce the restriction around Rockall from 7 June, Foreign Affairs Minister Simon Coveney and Fisheries Minister Michael Creed challenged its right to do so.

They both cited Article 121 Unclos, which provides that “rocks which cannot sustain human habitation or economic life of their own shall have no economic exclusion zone or continental shelf”.

But Professors Symmons and Long said this did not mean such rocks could not generate “territorial limits”, an argument similar to that made by Scotland’s Rural Economy Secretary Fergus Ewing.

Once the UK leaves the EU, Irish and EU vessels will no longer enjoy any rights to fish in British waters, Professor Long explained.

In the Dáil yesterday, Taoiseach Leo Varadkar said: “The waters around Rockall are part of the UK’s exclusive economic zone and they accordingly form part of the European Union waters under the common fisheries policy, to which the principle of equal access for all European vessels, including Irish vessels, applies. Irish vessels have operated unhindered in the Rockall zone for decades, fishing haddock, squid and other species.”