Episode 1
The recruits' first task is an unexpected one: writing an essay about themselves. Then they face an eight-mile combat fitness test while their essays are dissected for an insight into their character.
Episode 2
The remaining recruits must choose their weakest colleagues, who then lead the next exercise. And there's the 'Sickener': a series of physical challenges that won't end until five recruits give up.
Episode 3
The directing staff test the remaining recruits' resistance to fear, with mind games and an intimidating challenge to dive backwards from a cliff into the freezing sea 12 metres below.
Episode 4
The directing staff have to whittle the group down to the six they think may have what it takes to complete the final stage: a punishing 72-hour cat-and-mouse chase across challenging terrain.
Episode 5
The remaining recruits each face the final, notoriously gruelling stage of selection alone: 24 hours of interrogation. Do any of them have what it takes to succeed in the Special Forces?