“I was picked to be one of the core soldiers,” he continues.
“And I was asked to do this scene where a jeep just drives up to a burning wreckage with wounded soldiers in. The wounded soldier was John Goodman and I just said, ‘Well, can I just make a suggestion please? You know it’s D-Day +4, you wouldn’t just drive right up, you would stop short, survey the area just in case there’s an ambush'.
“And it’s really as simple as that, it was the right place, right time. Didn’t plan it. Just said it. He liked it and then it led onto other films.”
He says the length of time it takes to train actors in how to handle weapons depends on the historical era of the film: “If I’m working on maybe a Napoleonic, or sort of a Victorian-era type film, not much, because it’s muskets.
"You don’t want them looking too polished with those types because of the way the soldiers were taught at the time.
“If you’re looking at more modern [weapons], ... there's a lot of weapon handling, a lot of weapon training, safety that goes into the training of those actors.
He continues: "The weapons we use on set are actually live real weapons that just have a blank fire and attachment fitted inside the barrel itself and they are very powerful. And the actual blanks can kill.
"So it’s very important to train the actors to be safe but also look like they’ve been using these weapons most of their life.”
He also says the reason why most actors seem to have guns with unlimited ammunition is because of the way editing works:
“You get the term ‘Hollywood magazine’, which seems to be this magazine that is never-ending. I’ve had it on productions as well and obviously it’s a learning curve for myself and I’ve learnt the ways around it.
"What tends to happen is they get cut out during the edit stage. And the guys that are editing don’t realise that, you know, ‘that’s a bit boring, so let’s cut that bit out’, so that’s why you normally see a never-ending magazine.
“I tell the actors, ‘look, you know, change your magazine during dialogue, either it be a combat magazine change or a tactical magazine change. That way during the dialogue it’s less likely to be cut out.'"
Paul says for most of his work he relies on his own research, asking questions of contacts he has around the world, with the rest based on his experiences in the Army.
“You have to research because you can’t pretend you know everything.
"You have to look at the way the soldiers are trained, depending on what country they’re from. So, for example, if you’re representing some Russian soldier, he needs to handle his AK-47 as a Russian would handle it. From cocking it – he cocks it a different way to how a British soldier would cock his weapon.
"For example, in the private security sector, obviously a lot of British guys with AK-47s, they cock them as they cock an SA 80 – which isn’t the correct way to do it.”
Mr Biddis doesn’t just train the actors; he is also involved in helping the scriptwriters create a film that is as realistic as possible:
“My job is really to give them, for example, mission examples of how a mission may pan out, how the heroes could get from A to B, how could they break into this room and how they’re going to escape it once they’re cornered.
“I’ll give them certain scenarios which really wouldn’t happen. Just to try and cut out that sort of element and then once they finish that script, I’ll get given a script and I’ll give notes and give them examples of how they could get A to B and maybe cut that bit out because it’s irrelevant and put this in because it looks realistic.”
Mr Biddis has worked with a number of famous faces, but whilst he describes Matt Damon as a “really genuine guy to work with”, he says “Andy Hopkins was probably the highlight for me”.
For any military personnel hoping to break into the film industry, he suggests starting out at the bottom as an extra:
“The system is very much like the system they’d be used to in the Armed Forces,” he describes.
“There is a rank structure, there is etiquette.
"There’s a time when you have to say things and a time when you need to sit back and let it run. So yeah, to start as an extra is probably one of the best ways to actually learn about the industry but don’t expect just to get there just like that because it is a long run.
"It is something that you have to work at and there’s also a bit of luck involved. Like myself, it was luck. I was in the right place at the right time.”
RATED is on Forces TV (Freeview 96, Sky 450, Virgin 277, Freesat 165) every Tuesday at 12pm and 5pm.