Byline: Peter Ross

THE trick is to catch the apples before the dog gets them," says David Hamilton, glaring down at his nemesis - a springer spaniel blithely gobbling a piece of fruit. "It's a constant fight, isn't it, Rusty?" Hamilton, a tall, genial 38-year-old, is an officer with Tayside Police. He's the father of a 21-month-old daughter. He's also a transitioner, meaning he is part of a growing movement of people who believe in an urgent need to find new ways to live without oil. Today, that means collecting fruit from the trees in his back garden in Letham, Fife, and juicing it in an apple press which the North Howe Transition Toun - the group to which Hamilton belongs - purchased last year as a community resource.

The press gleams silver in the sun. As Hamilton turns the wheel, the juice flows autumnal and cloudy into a jug. Since this device became available, he has no longer had to buy juice from the supermarket, juice that may have travelled hundreds or thousands of miles, using a great deal of fuel, before ending up on the shelves. "My long-term plan," he grins, "is cider."

It's a small thing, pressing your own apples. But Hamilton has been making a number of small changes - transitions - in his life, and they are adding up. He has installed a wood-burning stove in the lounge and is one of a group of people who have bought an area of woodland from which they intend to gather their own firewood. He has had his cottage thoroughly insulated. He drives halfway to his work then cycles the rest. He plans to learn which wild mushrooms are edible, and how best to prune a fruit tree.

All of these activities are pleasant. It's nice to have a cosy house and fun to eat food you gathered yourself. But Hamilton, by his own admission, is no hippy. "I wouldn't," he says, "go out and hug a tree." His activities are more than mere dalliances. He is beginning to prepare for a future some believe is not too far away, in which the supermarket shelves lie bare and in which communities must learn to feed themselves or starve. "My prediction," says Hamid van Koten, a transitioner who lives nearby, "is that people will start ploughing Kelvingrove Park."

What is transition? A method of making an "elegant descent" from the oil-guzzling world we inhabit now to the post-oil future. The idea is to make that change gradually and without panic. The movement began in October, 2005, when Rob Hopkins, then a lecturer in his thirties, living in Totnes, Devon, began giving talks and showing films around the subjects of peak oil and climate change.

The concept of "peak oil" is crucial to transition, and is what differentiates it from other environmental groups. Peak oil is the point at which the maximum amount of oil that can be produced is being produced. It is a tipping point. From then...