The role of special observer is unique.
Their job is to march up to 100km ahead of the frontline - deep into enemy territory and in the dead of night construct observation posts in buildings, bushes or underground.
Then they must watch and wait, silently logging the enemy’s every move and feeding it back to command. The information they send will be crucial.
5 Regiment Royal Artillery midway through a 13-week course, where the next batch of recruits are being taught to construct observation posts.
"I think [running] through my mind is, you know, ‘What if we do get caught? What is my plan to get out of that situation?’" said one soldier, who is currently training as a Special Observer.
“You never want to get caught when you’re the person hiding."
A crucial part of their training is how to build observation posts and march long distances.
“Most importantly we need to be able to speak to people and observe people. Next most important is that nobody sees us.
"That’s usually achieved by picking the most horrible, inaccessible place we can find. A place where nobody else is likely to just go by."
“Gorse bushes,” he added, “are particularly good for this type of training.
"They are really awful to try and get into but they do provide quite a lot of good cover."
Once a bush is located, it is hollowed out and a shelter constructed within it to protect them from the elements and hide them from enemy thermo imaging. The aim is to be completely invisible from just 5m away.
Once in position, the four-man teams must be self-sufficient for up to 10 days, during which they face hours and hours of watching in total stillness and silence.
“There’s no easy way of taking the boredom away,” says another soldier, “and each individual has their own way of keeping their mind occupied.
"I like to probably think of a song, ‘Shotgun’, you know ‘Aqua’ springs to mind as well, ‘Barbie Girl’!"
“It’s not for everyone,” says another soldier.
“A lot of people just don’t like being confined in that kind of environment.
"But the actual essence of going out and finding that target and then reporting back.
"You know that what you’re pushing back is critical information.
"What you say, it can change the entire picture of essentially a war. Four blokes sat in a bush!"