In 2015, Iran agreed a long-term deal on its nuclear program with a group of world powers known as the P5+1 - the US, UK, France, China, Russia and Germany. Our World reports on the process that led to the agreement.

More Americans die from drug doses than car crashes or gun fatalities. The majority of the deaths involve the use of heroin or prescription painkillers. Over the past year, Ian Pannell has followed a number of addicts as they try to kick the habit.