EXCLUSIVE: Oscar-winning director Kevin Macdonald (One Day in SeptemberThe Last King of Scotland) is on board to direct the politically-charged Guantanamo Diary for Benedict Cumberbatch, Adam Ackland and their company SunnyMarch and ZeroGravity’s Mark Holder and Christine Holder.

Michael Bronner is scripting the project which follows the tribulations of 45 year-old Mohamedou Ould Slahi, a man who was a suspected terrorist and had been incarcerated at Guantanamo bay for 15 years without ever being charged with a crime or having the opportunity to defend himself in court. He was let out only last year, quietly and without media fanfare. Also producing is Lloyd Levin and Beatriz Levin.

Bronner is a former 60 Minutes producer who has covered the Guantanamo story extensively. He was previously involved with and provided expertise and research for Paul Greengrass’s United 93 and also the Tom Hanks-starring Captain Phillips.

Slahi is the son of a nomadic herder who was — over years — subjected to “enhanced interrogation” techniques that include everything but waterboarding. His memoir claims that includes having his ribs broken, being kept awake for days, being blindfolded and taken out to sea where he was told he would be executed and was made to drink sea water, and subjected to sexual humiliation involving female soldiers. Yet never charged with a crime.

Convergent Media has been funding development on the project.

Macdonald won an Oscar for his documentary feature One Day in September and his gritty drama about military dictator Idi Amin The Last King of Scotland won Forest Whitaker his Best Actor Oscar. Macdonald’s previous credits also includes Black Sea with Jude Law and How I Live Now with Saoirse Ronan.

The filmmaker is repped by United Agents and WME.