The Unit: From March 7th, weeknights at 9pm on Forces TV - Sky 264, Virgin 277 and Freesat 652
The hit show The Unit is coming soon to Forces TV. To celebrate its arrival we thought we'd take a closer look at its inspiration - one of the most secretive parts of the US Army: Delta Force.
Delta Force, or The 1st Special Forces Operational Detachment-Delta (1st SFOD-D) as it's less snappily named, was formed in the late 1970s after a series of attacks forced the US government to rethink its counter-terrorism strategy.
It was the brainchild of a Colonel Charlie Beckworth, known as Chargin' Charlie, a Special Forces soldier who had served as an exchange officer with the British SAS during the Malayan Emergency. It took ten years however to persuade the Top Brass that an American equivalent to the much lauded and feared Special Air Service was needed.
In addition to covert operations and reconnaissance, Delta Force was designed to react to terrorist incidents such as plane hijackings and hostage situations. Its first high profile mission, to rescue American diplomats and civilians from the US Embassy in Iran, ended in failure.
Delta Force is understood to consist of around 1000 soldiers, drawn from the US Army and Marine Corps, all male and over the age of 21 - of which around a third are actually involved in direct operational action.
Internal advertisments for 'The Unit' - as those who work for it refer to it - describe it as "the U.S. Army's special operations unit organized for the conduct of missions requiring rapid response with surgical application of a wide variety of unique special operations skills."
The majority of Delta Force operations remain classified although there are a few instances where details have emerged - most notably Operation Iraqi Freedom and the subsequent capture of Saddam Hussein.
In October a Delta Force Master Sergeant, Joshua L Wheeler, died during a raid on an Islamic State prison in Iraq. Part of a 30-strong special forces team sent in to release prisoners in imminent danger of execution he died in a firefight. Seventy hostages were eventually rescued, twenty militants were killed and five captured.