A DUP MLA has claimed Northern Ireland's electricity grid is being run from the Republic of Ireland - despite being supposed to operate independently of its southern owners.
The System Operator for Northern Ireland (Soni) has been owned by Eirgrid, the Irish state-owned grid operator, since 2009.
It is a condition of Soni's licence that it operates independently from Eirgrid.
But North Antrim MLA Paul Frew said he is concerned that Soni's operating independence is unclear.
"They are owned by Eirgrid, which is owned by the Irish government," he said.
"I thought surely there are checks and balances in place to ensure risks around conflict of interest or independence are mitigated.
"The more I have looked at this, the more I have realised that it isn't the case. All the checks and balances that should be in place have been blatantly ignored by Eirgrid, to the point now that when I talk to Soni, I am not actually talking to them, I'm talking to Eirgrid," he told Dublin's Sunday Business Post newspaper.
In a statement, Eirgrid and Soni told the newspaper: "Over the past 11 years, Eirgrid and Soni have successfully worked together for the benefit of industrial and domestic consumers in Ireland and Northern Ireland, operating as separate licensed organisations within the Eirgrid group of companies.
"This model enables Soni to realise the synergies and efficiencies available to it as part of a larger group, while also ensuring Soni's singular focus of delivering positive outcomes for consumers in Northern Ireland."