“The announcement by US-owned National Grid fundamentally undermines UK energy security. This is a market-driven decision and not in the best interest of the UK,” said UNISON head of energy Donna Rowe-Merriman.

“This decision leaves UK energy security vulnerable. Any decision on the future of Grain LNG and National Grid Ventures must be part of a longer-term view in relation to energy policy and security. Any sale must be a political decision taking account of the impacts on the UK’s future energy security.”

Located on the Isle of Grain in Kent, the LNG import terminal – Europe’s largest such facility – is being expanded and will soon be able to store and deliver enough gas to meet its target of about a third of the UK’s gas demand.