For the 18 remaining recruits, Ultimate Hell Week is about to enter an even tougher circle of challenge and torment. Lieutenant Dante Membrere is a serving officer in NAVSOG, the elite special forces of the Philippines. The unit is one of the most feared fighting forces in the Far East. Fresh from tormenting real recruits in the Philippines, he will be looking to find the weak link in the group, or virus as he calls it. Dante will push the recruits through 48 punishing hours where they must prove they can cut it as a NAVSOG recruit, from carrying 180kg logs as they race to save a casualty, to NAVSOG's version of the Ironman. Those who can navigate their way out of the mountains will face Dante's sickener, an endurance test that will push every one of them past their limits.

After three back-to-back challenges, the 13 remaining recruits are battered and bruised, sleep-deprived and physically exhausted. But they are about to face their toughest challenge yet, all under the orders of Jason Falla, a former member of the Australian SAS. For the first time, the recruits will learn what it is like to go behind enemy lines as they take part in a military role play to help supply a guerrilla force. Under Jason's eagle eyes, they will have to prove that they have the mental strength to operate in hostile territory whilst marching through the night and facing the demands of the guerrilla army. Who will be the first to break?

After surviving the first four brutal training courses, the ten remaining recruits are about to enter a more psychologically challenging phase - the world of the Russian Spetznaz Special Forces, under the authority of veteran Sonny. With only six places available in next week's grand final, the recruits will have to draw on every ounce of their depleted reserves to make it through 48 hours of rigorous mental and physical testing. From carrying heavy weights for miles through the gruelling hills of south Wales to having their wits tested under extreme mental endurance, the recruits will be marked down for the smallest mistake and any weakness shown could mean not making it to the final. Who will be in the final six?

They have survived the initiation programmes of five of the world's toughest army units. Now, for the final, the remaining six recruits will face the ultimate test - 48 hours with the British SAS. Few are chosen and even fewer can pass the intense mental and physical challenges that must be endured and triumphed over to stand a hope of being selected for this most elite of forces. But at the end there can only be one winner. Who has what it takes to take the title of Special Forces: Ultimate Hell Week?