Royal Marines, modern day commandos with a motto of 'By Sea, By Land' love an estuary and we have our very own Commando Obstaclesat Hever Castle. Just keep pumping those legs and mind your head on the low bridge.

Commandos spend a lot of time on their bellies! Tunnel systems are often part of an established defence network and Commandos make it their mission to attack in the dead of night when enemy defences are at their weakest. Use your hands and knees and crawl fast.

These drainage pipes are often used as road culverts, which make excellent hiding places for roadside explosive devices places to disrupt enemy movement around the battle field. It's important to be able to navigate these quickly and efficiently.

Inspired by the Tarzan Assault course at the Commando Training Centre, Lympstone and one the Royal Navy's most daring missions in which 176 sailors and Royal Marines lost their lives.

Targets for Commando raids are often well defended and more often than not sit in commanding positions on top of hills. With the route pre-laid for you by a suitably steely mountain leader all you need to do is move uphill quickly using the ropes left out for you.

Commandos on raids often have to support their body weight on pre-set scaling ladders and often there will be a considerable drop below. Balance beams and rings are also available to use.

Commandos often conduct operations from small boats and have to board much bigger ships. Often the steep sides of these ships will be scaled using scramble nets and it is this, minus the rolling deck in heavy seas, that we have replicated.

Commandos often have to adapt and overcome obstacles at speed and whilst under fire. Trust your instincts and go for this!

Royal Marines need to adapt to all conditions and finding their way in the dark and unfamiliar situations is up there. Sit down, lie back, shuffle forward using your heels and shoulder blades, stay straight and don't look down.

Commandos have used cave systems as a means of covert approach. Feel the walls as you make your way through this tunnel system and watch out for the creepy crawlies.

Often a covert approach will involve a long silent patrol up a river or stream where the scouts will have laid a rope to assist with navigation and deeper sections of the water. Just follow the rope and trust the Commando in you!

The "Commando Crawl" is a technique practised by modern day soldiers and it enables fast movement over rough ground but without exposing the person to enemy fire. Keep your backside down and use your elbows and the inside of your knees.

Commando raids are often staggering in their speed of execution. A well drilled patrol can cross a fast flowing river in a matter of seconds. Listen to your instructor here and they will explain the techniques. Prepare to get wet!

Faced with crossing a wide stretch of river, recruits must pull themselves and their team safely across. Engage your core muscles and use long, wide tugging motions to pull your team across the river.

Adapt, overcome and have a bit of fun. Commandos, renowned for their sense of humour in adversity, will often cleverly adapt equipment and other bits of kit left around to suit their purposes. In this instances we have used tractor tyre inner tubes.

The enemy will often try and slow your progress down with man made obstacles. Beware of booby traps through. Play with a leap and a gate vault as a team.

Designed to simulate a large chasm, canyon or danger river crossing. This time you can cross using the Tyrollean Traverse or, like the real deal, the suspended Commando Crawl. The obstacle replicates what the Royal Marines call "the tank".

Commandos will often have to navigate a makeshift bridge as they quickly cross rivers and larger streams. Stay low and don't hang around. Trust your balance.

Sometimes in a Commando's life the only way is the hard way. Not everyone's idea of fun, just hold your breath and let our instructors do the work!

Clamber up the gate using the crossbars as footholds. When your midriff reaches the top bar lean over and grab a rail in line with your feet on the other side and then, using that core again, swing your lower body over the gate to land two-footed on the other side.

Often the last and hardest part of any raid - the scaling of the ramparts or walls. This 12ft wall with suitable trail rope and footholds to assist your progress would have been scaled by one of your mountain leaders in advance. You've just got to get to the top!