Long believes it is important for younger generations to read these letters, and learn about the man whose work still impacts lives.

"I think this is the kind of study that makes us rethink what is aggression and what are its causations and mechanisms of action," Hanlon said.

I like to take photographs to capture a moment that I can later share with my family and friends so they can see what my life is like.

But for a short ride I like to go to Kirirom National Park – it’s a wonderful track, 960 metres elevation, with a pine tree jungle providing shade for the riders.

But by accepting the principle that spending must fall, Mr Cameron says he has already been braver than the government.