The world is in the grip of a costly, destructive and quite often deadly environmental crime of which most people have never heard.

Communities around the world are waking up to find their local beach, riverbank or lake have been stolen by a very 21st century branch of organised crime: the sand mafia. These criminal gangs control governments and may be raking in over $70bn globally each year.

And those who try and stop them are being killed in their hundreds.