There are an estimated 875 million registered firearms in the world. And each year, that number goes up by hundreds of thousands. Three years ago, arms experts spotted a single advanced Belgian rifle in the hands of militants in Gaza. But how had a group listed by the EU and the US as a terrorist organisation obtained the weapon? Arms expert Nic Jenzen-Jones and the BBC’s Thomas Martienssen have tracked its journey.

Subscribe to BBC News HERE
Check out our website: