Bonnie can sniff out a single hidden 5.56mm bullet
Lance Corporal Jenny Chester, 19, and her dog Bonnie are leading the Black Watch's defence against suicide bombers.
L/Cpl Chester and Bonnie go forward alone to check cars for devices at vehicle checkpoints in Falluja while soldiers wait in armoured Warrior fighting vehicles.
They were rushed up to the 850-strong battle group's base at Camp Dogwood, 25 miles south of Baghdad, five days ago after receiving an urgent call for their services.
They were previously deployed on a four-month tour in Basra and had been due to fly home to Britain this Wednesday.
L/Cpl Chester, from Kent, said: "It was a bit of surprise coming up here. But that's the job and it's good to be useful."
Following the deaths of three soldiers in a road block attack, Black Watch chiefs have changed tactics.
Traffic in and out of Falluja is now stopped by barbed wire and Arabic signs, 100 yards away from troops' positions.
Drivers are ordered out of their cars over loudspeakers and told to open their shirts so that soldiers can make sure they do not have explosives strapped to their waists.
At this stage, L/Cpl Chester and Bonnie approach and sniff out vehicles for weapons and explosives.
The soldiers will only approach after L/Cpl Chester gives them the all clear.
L/Cpl Chester said: "Of course it's scary when you think what could happen when we approach target vehicles.
"But I'd rather it be me and my dog than five soldiers."
She denies she is doing anything courageous.
"Am I brave? Not really. Everyone's brave in his or her own different way out here.
"I do it because I trust Bonnie 100%. I know if there's something there, she'll find it and hopefully we'll be able to get out of there in time".
The pair trained for three months together at the Military Working Dogs Support Unit HQ in Leicestershire.
Bonnie can sniff out a single hidden 5.56mm bullet under a pile of other objects.
Black Watch spokesman Capt Tim Petransky said: "They are an incredibly useful asset.
"Explosives dog handlers are very dedicated and brave people and the presence of L/Cpl Chester and Bonnie on Operation Bracken is invaluable."
Another Camp Dogwood hero is Cpl Colin Hamilton who lost his right leg above the knee and received serious burns when he suffered an electric shock while on tour of Kosovo three years ago.
When he was told he would not be allowed to go to Iraq with Black Watch because of his disabilities, he launched a one-man battle to persuade his bosses to change their minds.
They consented after he ran the second fastest time for an 800m run by a military amputee.
Cpl Hamilton, from Dumbarton, said: "I'm just a jealous person, I don't like being left out.
"But I've proved I can do my job just as well as anyone now.
"As far as I'm concerned, being back with my mates is the best form of rehabilitation you can get."
From pool reporter Tom Newton Dunn of the Sun at Camp Dogwood. Pictures from Heathcliff O'Malley of the Daily Telegraph.