Slovakia’s prime minister said soaring electricity costs had left his country’s economy at risk of “collapse”, in the starkest comments yet by an EU leader on the effects of the global energy crisis.

Eduard Heger said the huge increase in prices following Russia’s full-scale invasion of Ukraine would “kill our economy” unless Slovakia received billions of euros of support from Brussels, and warned he would be forced to nationalise the country’s power supplies if this was not forthcoming.

Although Slovakia is a significant producer of nuclear and hydroelectric energy, its biggest energy provider made a costly decision to sell off its excess power to energy traders early in the year. These traders are now selling the contracts back to Slovakia at market prices that are about five times higher.