EDF Energy on Thursday bought 10 salt caverns in Cheshire, north-west England, for gas storage to ensure supplies keep flowing when imports dry up.

The UK has dwindling gas reserves and a chronic lack of storage capacity so the deal with British Salt should allow Britain’s largest electricity generator to keep customers’ lights on even if there are disruptions to supply, as seen over the last two winters when Gazprom, the Russian energy giant, restricted the flow through Ukraine in a price dispute.