In this first episode, the 29 recruits meet Ray and Woodie, two former members of the US Navy Seals, who are about to put them through a beasting or 'breakout' – four hours of PT amidst continuous cold water hosing. And that's just the start. And so begins two days of hell at the hands of our battle-hardened Navy Seals. Who of our 29 recruits will survive and who will be sent home?

29 started, now 22 remain. Episode two sees recruits under the command of former Israeli YAMAM operative Itay Gil. He is looking for strong leadership under extreme pressure.

Brutal challenges result in hospitalisation and failure. Recruits get up close and personal with Israeli self defence system Krav Maga, strive to remove a Land Rover from a mud pit with their bare hands and are pushed beyond their physical limits in a punishing weight bearing race.

Only the strongest in body and mind will make it through to the next 48 hours of Special Forces: Ultimate Hell Week.

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 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?