The European Commission has cleared Centrica's €1.1 billion takeover of Bord Gáis Energy, the retail arm of Bord Gáis.
The EU's executive ruled that Centrica's expansion in Ireland did not pose any problems to competition in the energy supply market and that Bord Gáis' UK business was not large enough to give Centrica any competitive advantage there.
"The Commission concluded that the transaction would not raise competition concerns," it said in a statement today.
Bord Gáis Energy has 900,000 gas and electricity customers across the country. The deal also includes the sale of the Whitegate gas-fired power station in Cork.
The deal is expected to close in the coming weeks.
Under the terms of the deal announced in March, all Bord Gáis Energy staff will transfer to the new group with their existing working terms and conditions.
The State will retain ownership of the natural gas network, which transports gas, as the Government believes that this is strategically important.