Tungsten is one of the hardest, heaviest and highest melting metals, used in everything from bulbs to bullets, x-rays to drill bits. Justin Rowlatt hears from the perennial Professor Andrea Sella of University College London about the properties of what is one of the densest of elements.

Should we worry that China dominates demand? And why is it taking so long to open up new sources? We visit the Hemerdon mining project in the pretty English county of Devon, and hear from Russell Clark, head of the mining firm Wolf Minerals that is reopening it.

And, there is a very special reason why your government should care about its tungsten supplies, as military technology analyst Robert Kelley explains.

(Picture: Soldier lays armour-piercing sabot round on the ground during Operation Desert Shield; Credit: US Department of Defense)