Ben Cohen

In the brutal heat of North Africa, 14 British and Australian celebs take on an SAS selection course. First up is an underwater drill, and then it's Brits vs Aussies in hand-to-hand combat.

Phase two pushes recruits to breaking point with psych tests, split-second life and death decisions, terrifying mud tunnels and a brutal beasting that forces one of the celebs out.

The remaining recruits are hurled into an escape drill with a ladder suspended 15 metres up, which must be crossed while under enemy fire. And a punishing race to a mountain summit with 100kg of kit exposes one recruit's leadership shortcomings.

A race up 27 flights to the top of a dam pushes the celebs hard. Then the recruits must rappel 45 metres down the dam before free-falling eight metres into turbulent water. A high-stakes rescue in a war-torn village tests the recruit's moral courage.

The emotional strain is cranked even higher as the escape and evasion challenge leads the remaining celebs into the darkness, where they must somehow navigate through the unknown.

The recruits endure a brutal mountain ascent before facing a terrifying high-wire traverse 165 feet above a canyon. Billy forces recruits to write a final goodbye to loved ones, and then comes hand-to-hand combat with the Redman.