Nuclear security

EXCLUSIVE: Nuclear expert raises terror fears over Britain's huge plutonium stockpile

According to official figures more than 126 tonnes of civil plutonium was being held in the UK as of December 2014, with just 3-4 kg of the substance needed to power a nuclear weapon.

The world's largest store of the radioactive substance is held in Britain after successive governments accumulated plutonium from the 1950s onwards when it was widely believed to be a miracle replacement energy source for oil, coal and gas.

But attempts to use plutonium - among the world's most toxic substances - as a fuel have routinely been abandoned with Britain's experimental nuclear power plants now closed following a lack of success.