Ukraine has been left “one step away” from catastrophic nuclear meltdowns because of Russian bombardments of its atomic power stations, the nation’s energy minister has warned.

Missile attacks on the three nuclear power stations left under Ukrainian control, as well as their associated substations, cables and cooling equipment, are putting Europe at risk of a cloud of nuclear radiation escaping into the atmosphere, according to German Galushchenko, who oversees Ukraine’s energy systems.

“Russia has been attacking the substations supplying independent cooling power to the nuclear station. So when there is destruction of these power supplies, the nuclear units go into an emergency shutdown regime,” he said.

“The electricity for cooling then has to be supplied by a reserve diesel generator – but this is dangerous [because reserve generators can fail].

“We have been one step short of a nuclear meltdown many times now.”

Mr Galushchenko’s warning came after attending a global energy summit in London last week, where he compared the potential impact of such a meltdown with Japan’s nuclear catastrophe of 2011, when an earthquake severed the back-up power lines to the Fukushima nuclear power station.