The paratrooper he is bawling at is actually firing blank rounds during this exercise but his trainer's message is clear – there will be no second chances in Afghanistan.

Tomorrow the paras will swap to live ammunition and the risk of a "blue on blue" shooting heightens the need to stay sharp.

Sgt Johnson is taking men from the 4th Battalion, the Parachute Regiment (V) through an eight man section attack on a hilly firing range.

The 'V' stands for volunteer, but these are no weekend warriors.

In less than a month they will be stationed somewhere in Afghanistan, in the Middle East, among the dust and the bullets with the Taliban as their enemy.

Brotherhood

For this week, home for 27 of the regiment's paratroopers is the coastal training barracks at Kirkcudbright, pronounced 'Cucoobry', in south west Scotland.

Private James Jesson, from Wetherby, who normally works for Leeds City Council's parks department, said: "The whole job of being a paratrooper is being able to think on your feet and look after each other in the field.

"We've already done two weeks training in Nottingham and will do another week in Yorkshire before deployment.

"You're basically meeting up with old friends and we all tend to keep in touch in civvy-street.

"There's something called the airborne brotherhood – if you've thrown yourself out of an airplane you all get on because the training is so bloody awful.

"The Marines bang on about their training, but they're just ramblers with woolly hats on!

"But seriously, this is the reason we are here – to train and run through the skills we will need in Afghanistan.

"Some of the blokes have been training for this type of deployment for 20 years."

Craig Allen, from Halifax, is one of them.

A full-timer with 1 PARA for 23 years, he re-joined with 4 PARA at Thornbury Barracks near Pudsey in 2002.

A freelance photographer in civvy-street, the 47-year-old is the Parachute Regiment's official unit snapper.

He said: "I think the training is concentrating everybody's mind.

"I've had a five tours of Northern Ireland, as well stints in Bosnia and Iraq in 2002.

"The likes of myself, and the full-timers who will be with 4 PARA, have an idea of what we're going in to.

"Another advantage of 4 PARA is that you get guys who aren't just straight out of school.

"They have a breadth of experience inside and outside the army which can make a difference to how they react once they're in theatre (the combat zone)."

A conversation the night before the exercise with some of his colleagues back in their shared quarters illustrates his point.

Jim Wilson, 34, from Clapham, is a corporate lawyer in the City of London and a reservist for 17 years, having joined as a school boy.

He said: "I was involved in force protection in Iraq in 2004, but Afghanistan is a totally different theatre.

War

"Unlike Iraq, which was an invasion by the Coalition Forces, this is much more the front line of the war on terror.

"It's a NATO operation and we are there at the request of the Afghan government."

Room mate Joe Whittaker, pictured left, from Stratford, is the youngest member of the training squad.

Still yet to earn his wings (you need to complete eight parachute jumps), the 20-year-old is well versed in the folklore of the Maroon berets.

But his enthusiasm is tempered by his more experienced colleagues.

Private Whittaker said: "We might take the mickey out of the Taliban but they've been fighting since the Russians invaded in the 1980s.

"We have to respect them as fighters and we have to convince the people of Afghanistan that we're not just a token gesture. I suppose it's hearts and minds as well as being there as a fighting force."

Anthony 'Flem' Fleming, 22, from Newcastle, joined in 2002 and is a bit of a joker.

"Part-time airline mechanic, full-time dare-devil," is how he described himself, not entirely seriously.

But when it comes to the job at hand the fitness instructor is deadly serious.

He said: "It's essential we're at our peak when we get to Afghanistan. Having said that I hate parachuting - which is ironic because I've done 42 jumps."

Ex-plumber John Dean, 37, from Liverpool, is a full-time reservist soldier (FTRS) with 4 PARA having first done his para training back in 1987.

Comrades

He is what you might describe as 'old school' and his attitude to those reservists and TA soldiers who don't mobilize when the calls comes is straight forward.

He said: "You're in the reserves for a reason, and that's to serve when asked."

Back on the firing range Sgt Major Johnson, himself a full-timer with 1 PARA, says that five or ten years ago reservists might not have expected to see active service during their service.

Now these part-time soldiers are a vital part of the British Army, standing shoulder to shoulder with their full-time comrades on the front line.