The BBC assesses how strong the army really is - in 45 seconds. Iraq's army benefited from years of US and British training, as well as billions of dollars in military aid, as it was rebuilt following the US-led invasion in 2003. But it has suffered a string of humiliating defeats by far smaller numbers of jihadist militants from Islamic State (IS) since January 2014. Video produced by Michael Hirst and Sara Barman