PREVIEW: SAS Who Dares Wins (EP2), Channel 4

After a physically and psychologically intense introduction to their SAS selection, the obstacle for the 17 remaining recruits to overcome over the next 48 hours is fear, as they are sent deeper into the wild and unforgiving terrain of the Isle of Raasay in Scotland.

Do they have the mental and physical robustness that they need? The recruits are put through their paces in a forward abseil; exposed to extreme cold in a water immersion exercise; required to operate as a team in a pitch-black disused tunnel; and they're forced to channel their aggression while enduring an arduous beasting by the DS.

SAS: Who Dares Wins continues Sunday at 9pm on Channel 4.