HE has witnessed first-hand the horrors of wars and natural disasters.

And amidst all the carnage and chaos he has kept a steady hand to save the lives of countless children and adults.

Dr David Nott has spent 25 years dodging bombs and bullets, and facing up to the worst that humanity can muster.

From Afghanistan and Sudan to Iraq and Syria, the Welsh surgeon has worked in makeshift and often clandestine hospitals to help the wounded.

Putting his own life on the line to save others has become second nature for David.

On Sunday, June 16 he will share his story at the Borders Book Festival when he delivers the McInroy & Wood Lecture.

David, who released his memoirs, War Doctor: Surgery on the Front Line, earlier this year, told the Border Telegraph: "I often get asked why, but working in these war zones provides a lot of satisfaction for me.

"In the midst of some of the most unimaginable suffering you meet some of the most wonderful people.

"Yes, I come home stressed, but you get over it quickly and get ready to go again.

"If you can help someone live, or even just smile as they are dying, it is worth all of the danger and all of the dismay you feel at what's going on."

As a fresh-faced surgeon in 1994 David Nott volunteered to work in the besieged city of Sarajevo.

The capital of Bosnia and Herzegovina came under military siege for almost four years.

Close to 14,000 people were killed as war raged and many, many more were injured.

But Dr Nott's first volunteering mission to save lives didn't initially go to plan.

He explained: "As a young man who had never been near a war zone before it was really dramatic.

"When I arrived at the hospital, though, nobody knew I was a surgeon and for the first few days I was told to brush out the theatres.

"It was only when one of the surgeons was leaving that I got my chance to help. It was great to actually help seriously injured people.

"I got the bug for flying into war zones and helping - and I've been doing it ever since."

Since Sarajevo, David has flown into more than 20 of the most dangerous war zones on the planet.

He's operated on hundreds of injured men, women and children in the likes of Gaza, Haiti, Libya, Chad and Sierra Leone.

Despite the extreme horrors he's witnessed, there is one conflict which has affected him more than any other - the devastated Syrian city of Allepo.

He continued: "By the time I first arrived in east Aleppo with Syria Relief in August 2013, many of the more senior doctors and surgeons had already left.

"It was in Syria that I began to get seriously angry about the inability of the major powers to prevent hospitals and medical staff being targeted.

"As many as 95 percent of the city’s physicians had found a route out.

"Those who remained were brave and committed, but there were very few of them and the risks were considerable.

"Clinics were assigned code names to disguise how many there really were.

"Ambulances carried no sirens or insignia and at night drove with their headlights off.

"Anything that looked like help for the injured was seen as aiding the rebels, and so a legitimate target for the regime."

Driven both by compassion, the desire to help others and the thrill of extreme personal danger, David is now widely acknowledged to be the most experienced trauma surgeon in the world.

But he began to realise that flying into a catastrophe was not enough.

Doctors on the ground needed to learn how to treat the appalling injuries that war inflicts.

And since 2015, the foundation he set up with his wife, Elly, has disseminated the knowledge he has gained by training other doctors in the art of saving lives in the most awful of conditions.

During next month's McInroy & Wood Lecture at the Borders Book Festival David will discuss the work of his charitable foundation as well as the political situation which has led to such bloody conflicts across the world.

But even from a man who has experienced the worst of humanity, David still has a few lighter stories to tell.

As well as saving lives in war zones he has flown into several natural disaster areas, including Nepal following the major earthquake in 2015.

He said: "I was expecting to spend my time in Nepal treating people for crush injuries but I worked the entire three weeks out there as an obstetrician, delivering babies and helping midwives.

"I lost count of the number of babies I delivered."

Dr David Nott will deliver the McInroy & Wood Lecture at the Borders Book Festival at 8pm on Sunday, June 16.

Tickets, priced at £15 and £13, are available from the Book Festival Box Office at www.bordersbookfestival.org or 0131 473 2000.