CHRIS Ryan apologises if he seems a little tired. "I came back from Brazil at the weekend and my nerves are a bit on edge. I'd only been there two days and people were shooting at me," he says, wearily.

For a man who spent a decade in the Special Air Service regiment (SAS), arguably the most feared and respected special forces institution in the world, his admission comes as a slight a surprise. Surely he'd be used to it by now? "You learn to recognise how close bullets, are but you're not immune to them."

Ryan has been in Rio de Janeiro, filming the first part of a new
TV series where he joins elite police teams out in the field. On this occasion he was working with the Bope, one of Brazil's crack military units which, as he puts it, "has a reputation for shooting first and asking questions later".

He admits that going into Rio's favelas, or shanty towns, and hunting down drug gangs was an eye-opening experience – even for him.

"I saw why kids end up in a life of crime. They have little choice and no rights, they live in a world where running gun battles with AK-47s, M-16s and grenade launchers are part of everyday life," he says. "There are more people killed in these favelas on a daily basis than there are
in Baghdad."

His next stop in a couple of weeks is Colombia's capital Bogota, where he will join police teams before heading into the jungle to seek out and destroy illegal drug factories. But in the meantime he's embarked on a whistle-stop tour across the North of England to promote his latest novel, Vortex, the fourth in his popular Code Red series.

The story is set in his home county Northumberland and, revealing another fascinating side to his personality, he's using one theme in the book to raise awareness of the Royal Society for the Protection of Birds campaign to stop the illegal killing of birds of prey, particularly hen harriers.

"In Northumberland, there are only three breeding pairs left because their nests are being destroyed. These birds hunt
on grouse moors, like the one where the fictitious military
base is set, and landowners
get the gamekeepers to go out and kill them.

"But I don't believe for one moment these birds destroy a grouse moor, and it's terrible to think that hen harriers could be extinct in this country within 10 years." A former elite soldier may seem an unlikely ally to an endangered bird of prey, but Ryan believes it would be a travesty if they disappeared from our countryside.

"They're beautiful birds to watch. The Harrier jump-jet is named after them, and they are up against foxes, rodents, polecats and the weather, so I'm on their side."

Ryan himself has come close to extinction on more than one occasion. In 2003, he nearly froze to death while filming Hunting Chris Ryan for the BBC when he was pitted against an international team of former Special Forces soldiers in Siberia. "When I set off it was about –10C but then it dropped to –46C, I lost feeling in my hands and feet and my equipment froze.

"I climbed into my bivi bag and eventually managed to make contact with the team. When they found me the medic said my core temperature had dropped to half a degree off death. Another 40 minutes and I would have been dead."

Ryan became a national hero following his incredible escape from Iraq during the first Gulf War in 1990. He was the only member of an eight-man team, part of the Bravo Two Zero patrol, to escape after being deployed behind enemy lines. "We were ill-equipped and ill-informed," he says. After coming under attack from the Iraqis the team was split up. "During the day I would try and rest which was difficult because I was lying in a stone hole, not able to move, in temperatures below zero and
two men died.

"I actually lay next to one man as he was dying. I had no food or equipment, I had no water for the first two or three days and then I was drinking river water from the Euphrates."

He was all alone and spent the next seven days trying to thread his way 200 miles across inhospitable terrain to Syria, walking up to 25 miles each night. By the time he got there he'd lost more than two-and-a-half stone in weight.

"I was in a bad way, I lost all my toe nails and the blisters on my feet had turned septic. My feet were the worst thing because it felt like you were walking on
bare skin.

"I'd been drinking water that had been contaminated by a factory producing uranium, which burnt my mouth. I suffered internal damage because I later had these
red patches that came out
on my face."

Three of his colleagues died and the other four were captured, and Ryan admits it's the hardest thing he's ever had to endure. "In my heart of hearts I know I couldn't have taken much more. I was close to death. I was covered in bed sores and I'd suffered sleep deprivation."

However, it was almost a case of out of the frying pan and into the fire, when he finally staggered across the border into Syria. First a lynch-mob tried to force him back to Iraq; then he was threatened with execution before the secret police fed him, gave him a suit and offered to show him the sights and sounds of Damascus night-life.

"In 24 hours I went from being on my knees in Iraq, to facing a lynch-mob and being threatened with execution, to being given a new suit and offered the chance to get my leg over." He makes light of it now, but what kept him going when most people would have collapsed?

"My training saved me and so did my two year-old daughter," he says. "When I was hallucinating, she appeared in front of me. The other thing was fear. If you think you're going to be executed, or killed, it drives you on."

Ryan is affable and polite, and while some may think he has a death wish, he believes such close encounters merely come with the territory. But as a youngster it wasn't action and adventure that attracted him to the Army. "When I was a kid we went to places like Bamburgh on holiday, and I wanted to travel and I thought the easiest way to see the world was to join the Army."

After joining the territorial SAS while he was a teenager, he went on to serve with the Parachute Regiment before joining the SAS in 1984, eventually becoming sniper commander of the anti-terrorist team.

His final two years in the regiment were spent as an instructor, but having to bury so many friends finally took its toll.

"The first guy I passed as a trainer was the first guy to be killed in Bosnia. I knew him inside out and I sent him there. He got his head blown off and that shook me up and I realised it was time to leave."

After leaving the Regiment he trained professional bodyguard teams for high-profile families in the Middle East, before he was approached by a publishing firm to write an account of his dramatic escape from Iraq.

Since then he has written well over a dozen books, including his popular Alpha Force adventure stories for youngsters. He also gives
talks to rooms full of enthralled children.

"I don't glorify war or killing in my books, but you have to be honest, and one of the questions I'm always asked is, 'have you ever killed anyone?' I say 'yes, but it's something that haunts me'."

"I'm an unlikely writer, but if I can help make reading trendy then great.

"When you get a letter from a kid who has trouble reading saying how much he enjoyed your book, even though it took him three months to finish, that gives you a real sense of fulfilment."