By Caroline Wyatt BBC News, Helmand province, Afghanistan

Saving lives makes it the best job in the world, says Corporal Bates

Corporal Charlie Bates and Brandy, a six-year-old black labrador, work as a team on the front-line in Helmand province.

They're part of the 102 Military Working Dog Support Unit, currently attached to Delta Company, 40 Commando Royal Marines.

Every day they're on patrol with the marines, often walking ahead across the dusty fields so that Brandy can sniff out potential dangers from IEDs - improvised explosive devices - or other hidden threats.

Brandy is an explosives search dog and, as Charlie points out, a crucial canine part of Delta Company 40 Commando's operations here.

"Brandy's temperament is fantastic, and the best thing is that the lads love him to bits," says Charlie.

"Brandy has become a sort of mascot for Delta company here, and so he's good for morale as well."

'Very rewarding job'

Brandy and Charlie walk ahead through an eerily deserted Afghan village - near a spot where other IEDs have been found before by British patrols.

So Brandy keeps his nose to the ground to sniff out any booby traps that may have been laid.

We can save lives on the ground, and hopefully that's what we will continue doing Cpl Charlie Bates

Despite the dangers, both dog and handler seem to enjoy their job - Brandy treats patrols as a long and exciting walk, while 26-year-old Charlie relishes the challenge.

"I've always wanted to work with dogs and I've always been interested in the armed forces," he says.

"So put the two together, and it's the best job in the world.

"I get paid to play with dogs, and it's very rewarding. We can save lives on the ground, and hopefully that's what we will continue doing."

This time, no IEDs were found in the village, and the patrol came safely back to base.

To work on the front line, Brandy had more than 20 weeks' training, and for his handler Charlie, it was four years.

Military working dogs are mainly donated by the public or by dog rescue homes, and are tested for aptitude. Once chosen, they work until they are eight years old, and are then found new homes as pets.

Brandy and Charlie may not have been a team for long - only since their current tour started in September - but they've certainly bonded.

"The individual dog relationship with a handler is massively important," confirms Cpl Bates.

"The reason for that is you have to know the dog inside out, both its indication if he finds something in an area, and also his general health - if he's having a good day or a bad day, how he feels depending on the heat, how hard we work the dog, when they need to have a break, or have water, things like that."

Back at their forward operating base in the Gereshk Valley, Brandy is welcomed warmly by the Army medical team he shares his sleeping space with.

The labrador has, of course, managed to find the comfiest berth in this rather basic camp.

In the only proper building with heating, he sleeps in splendour on a sheepskin rug - and snores, according to one of the medics.

Brandy gets the occasional treat on top of his usual rations

As darkness falls, it's time for Brandy's favourite part of the day, prompting even more tail-wagging than usual. It's dinner-time dog rations, which he gulps down greedily.

"He's a typical labrador - he'll eat anything he can get his hands on," Charlie smiles.

"He might get a treat now and again, but usually he just gets his normal dog rations."

'Brandy! Leave...'

They do say never work with children or animals - and they may be right. Brandy has been well-behaved all day, but suddenly the BBC microphone proves too tempting to resist, just as I ask Charlie what qualities the Army looks for in its sniffer dogs.

"The qualities we look for are individual temperament, and we make sure they're agile, with a good searching ability."

Suddenly, Brandy is off with the fluffy end of the microphone, shaking it playfully from side to side.

"Brandy! Leave it...leave!" commands Charlie, looking rather sheepish as Brandy refuses to return it.

Eventually the labrador is coaxed into dropping it, going back to his usual immaculately-behaved self.

As darkness falls, Brandy and Charlie sit under a starry Afghan sky by a small fire that one of the medics has lit in an old ammunition box, as the team tries to stay warm in the freezing cold Afghan winter's night.

It's the end of a long working day for both Charlie and Brandy, and tomorrow they'll be on the next early patrol at 0500.

I ask Charlie what the appeal of such a dangerous and tough job is.

"If Brandy and I find just one IED or explosive on a six-month tour, then it's worth it," he says.