Battle for Iraq: BBC finds military retreat in Anbar
Anbar - Iraq's biggest province - has seen some of the deadliest fighting against Islamic State (IS), with more than half a million people forced from their homes.
It is a vital supply route for the militants in Syria, and leads all the way to the outskirts of Baghdad.
At its heart is the once secure Ain al-Asad airbase, where Iraqi troops have been losing ground. If it falls, it will be a major victory for IS.
Journalists have been unable to reach Anbar since the IS swept through the province - but BBC Middle East Correspondent Quentin Sommerville and cameraman Tim Facey travelled to the airbase for this exclusive report.
19 Dec 2014