THEY have the same brown eyes and, despite the four years between them, the same missing front teeth.

Mike, the eldest, is brunet. David, his brother, blond. Heads together, they beam their smiles in to the camera.

This is just one snap, with the ever-so-slight blur of the early 1970s colour film, in the Haines family album. In another, Mike and David, ride on the back of their dad, Chris. In their wee white vests.

Nearly half a century later, Mike, now 52, has just shown his old slides to a room of London teenagers.And he has just described how he had had to tell Chris that David had been kidnapped in Syria, by so-called Islamic State. And then, eighteen months later, beheaded.

His message is simple: hatred, vengeance, is a choice you do not have to make.

How does he get that over? He admits the appeal of rage. “I say I have a battle with hatred each and every day,” he explains. “But that taking that path of hatred is exactly what the extremists want us to do."

Even David’s murderers themselves later killed admitted the 44-year-old’s death was pointless. The Haines family had asked for the men, including Mohammed Emwasi, or “Jihadi John”, the English-accented violent Islamist, be spared. But they too perished, along with perhaps half a million others, in Syria’s bloodbath. Emwasi was killed by a US drone strike a year after David.

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Another family snap

A former airman from Dundee, Mike has been telling people not to hate since the day after he learned his brother was lost. Last week he got an OBE for his efforts. John Swinney, the education secretary, has, Mike says, “cut through bureaucracy” to get him into more Scottish schools.

READ MORE: Brother of Scottish aid worker murdered by Islamic State terrorists calls for calm and unity

He is just off a stage at another school, Alec Reed Academy in Ealing this time. He is tired.

“I have given this presentation hundreds of times. I still feel the emotion. I still often have a tear in my eye,” Mike explains. “I feel that if I tried to choke back that emotion or don’t show the emotion, then what I am saying becomes a lie and everything I say becomes a lie.”

Many of the youngsters he talks to - they are aged between 14 and 18 - have never heard of his brother. Or his horrific end. They enter the room, hands in pockets, uninterested. They leave, he says, their “backs straighter”. Somehow, the youngsters connect.

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The Haines brothers with dad, Chris

"When I stand out in front of them you can see the confusion,” Mikes says over the phone from Ealing. “’Who is the fat old so-and-so out front? “What is he going to bore us with today? And then as I am showing childhood pictures of my brother and myself.

“My mum took a lot of photos. They were out of focus, blurry, the usual home photographs. I think the youngsters can see something of themselves in the picture.

“It might be a different culture or a faith. But the love between the brother and myself. They can see that.

“You can see the curiosity. Then when I take them to the kidnapping there is that realisation 'oh my goodness me, he is talking about his brother’.

“There is that sense of building horror to the point that he is murdered.

“I show one slide of my brother being threatened by Mohammed Emwazi and one of head and shoulders in the orange boiler suit.

“I tell the students he went through 18 months of torture. I don’t want to go into details. But I tell the students he got beheaded.

“That is enough detail for me, never mind them.”

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Mike and David Haines

David Haines, after secondary school in Perth, had been an airman and then an aid worker. He had helped people in the Balkans, in Africa and in the Middle East. He was in a refugee camp when he was captured.

His brother is not trying to turn him in to a saint. "He made bad decisions. He did less than honourable deeds. Like all of us, at times, he made mistakes. But what made David special is that he went to help his fellow man."

"He was four years younger than me. He was 44 when he died. 

"At secondary school, my brother's favourite words were 'I'll get my big brother on you'. I used to be skinny in those days. The amount of beatings I got because if my brother. He was a pain in the arse as little brothers are.
But I know I could count on him on every time. I wanted to go to Syria and get him out of trouble, like a big brother should. But I couldn't. 

"We might go months and months without seeing each other, but then we we did see each other it was like see each other the day before.

Mike has a charity, called Global Acts of Unity. Touring schools is now more or less his full time job, he says.

“It is my way of fighting,” he explains. “For my own sense of being. I have to fight them. I don’t just mean ISIS. I mean the far right and every type of extremism. Yes, they are the same....there is a symbiotic relationship between them. We have to tackle hatred head on.

"They murdered my brother but I am not choosing hated. So I tell the students if someone calls you a name, don’t you take that path. It just seems to work.”

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The brothers

How does he know his message get across? “It is the way that they are sitting. I am an ex mental health nurse. The body language. You can see that determination. They sit up straighter. They are engaged. You can see them ‘he’s not doing that, I’m not doing that’.

"One thing I have noticed, I have been in to madrassahs, Christian faith schools, very diverse schools and undiverse school, public schools, private schools, the hardest schools. I get the same response every time. Whether is it six students or six hundred."

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David Haines in captivity

He and David share values they got from their family. He says: "When we were kids we were brought up to despise racism and bigotry. When my brother and I went in to air force, one of the things we joined up for was to protect people of Britain. That sounds cliched but it is true. Anybody who was living in the UK."

How does Mike keep going? How does he keep revisiting the most painful, shocking moments of his life? “As the students come in,. few seconds before I am due to start, I have a wee moment to myself. I say ‘hey, bruv, give us a hand here.’

“And at the end, I sit down for a few seconds, I can feel him pat me on the back saying ‘nice one, now get the beers in’. That is very much how we were."