The point, says Stewart, is to change the way people behave. “In the world, everyone is just out for themselves,” he says. “And to an extent that works.

But I think when you start to put yourself last, you realise that it is the best way to live.” So the clothes are really just a prod in the right direction. “I want the logo and symbol to inspire people. Hopefully people will see it and recognise it, and think ‘Oh yeah – I should really do something for someone’. That’s the idea.”

He shows me one of the Ark tops. Each one sold has a cardboard tag, personally attached by Stewart, with one suggested act of random kindness. They read a little like the cards in a Monopoly game. This one says: ...

The point, says Stewart, is to change the way people behave. “In the world, everyone is just out for themselves,” he says. “And to an extent that works.

But I think when you start to put yourself last, you realise that it is the best way to live.” So the clothes are really just a prod in the right direction. “I want the logo and symbol to inspire people. Hopefully people will see it and recognise it, and think ‘Oh yeah – I should really do something for someone’. That’s the idea.”

He shows me one of the Ark tops. Each one sold has a cardboard tag, personally attached by Stewart, with one suggested act of random kindness. They read a little like the cards in a Monopoly game. This one says: “Pay for a random pump at the petrol station. This could be a costly one – but imagine if someone did it for you.” As he shows it to me, he can’t resist a little salesman’s pitch. “You can see, can’t you,” he says, “they’re class quality.” It does look like a nice shirt.

So did the clothes come first, or the concept? Was the idea always to change the world? “No,” he says. “No, no, no. It was originally going to be just for Cameron’s profit. And for me to be a millionaire by the time I was 20.

But then I realised that it’s more fun to give money away than to store it all up. So it changed to being a millionaire by the time I was 20, and giving it all away.” All the profits from Ark clothes go to charitable works – basically, acts of kindness on a larger scale. “When the whole business was building up, I made a group on Facebook,” Stewart says. “There are about 500 or 600 members now. And just before Christmas I sent out a message saying, if you see a need anywhere, just e-mail me and we’ll pay for it.”

So what have they done so far? “One girl e-mailed and said: ‘There’s a woman I work with who’s recently had a child. And she was back to work within a week of having the baby, because she doesn’t have any money and she’s really, really struggling.’ So I gave her some money, and t

So I gave her some money, and they made up a Christmas hamper and delivered it. We did a few hampers.” The group also delivered presents to a Belfast homeless shelter.

How did he get started in the clothes business so young? “Well, when I was in school, I was an entrepreneur at heart,” he says. “I could sell anything, and I always tried to sell anything. Just for the fun of it, I guess. And I started buying designer clothing online, and selling it online. And then from doing that, all these Chinese suppliers e-mailed me, so I ended up getting this massive list of factories in China. All these contacts.”

When he came up with the idea for Ark – and after his exams were over — he went to Chin...

So I gave her some money, and they made up a Christmas hamper and delivered it. We did a few hampers.” The group also delivered presents to a Belfast homeless shelter.

How did he get started in the clothes business so young? “Well, when I was in school, I was an entrepreneur at heart,” he says. “I could sell anything, and I always tried to sell anything. Just for the fun of it, I guess. And I started buying designer clothing online, and selling it online. And then from doing that, all these Chinese suppliers e-mailed me, so I ended up getting this massive list of factories in China. All these contacts.”

When he came up with the idea for Ark – and after his exams were over — he went to China himself to check he wasn’t buying from a sweatshop. “Thankfully, the first guy I met was just fantastic, and the factory was great. We drew up a contract and got 600 shirts ordered. It took a week.”

This is all highly creditable. But, I ask, doesn’t he miss normal 18-year-old activities? “I do miss Xbox and all that kind of stuff,” he says. “I would love to sit and do that all day. But I think this’ll be far more rewarding, even though it means answering e-mails all day.”

Cameron is sceptical about the idea of going to college. “The businessmen I aspire to be like don’t have degrees. They just started off. A lot of my friends have gone, but most of them are still based in Belfast, so I’m still kind of living that life. Apart from business meetings, and bank manager stuff, and all that.”

www.arkchangeyourworld.com