How worried should we be about 'nuclear terrorism'?

There are concerns about fissile nuclear material getting into the wrong hands that could have a devastating effect.



The Brussels attacks have highlighted the urgent need to make the world's supply of fissile material secure.

Two of the bombers appeared to have previously been monitoring a senior researcher who worked at a Belgian nuclear centre.

The White House reckons that around 2,000 metric tonnes of highly dangerous nuclear material is out there, in both civilian and military programmes around the world.

It is not just used in weapons of war. Highly enriched uranium and separated plutonium are used to generate power, and they are also widely used in medicine.

Early on in his presidency Barack Obama highlighted the risk of nuclear attacks, describing them as "the most immediate and extreme threat to global security".