It’s late afternoon and a darkening sky and gusting wind promise rain. Fifteen miles from civilisation, I’m wearing trainers, no waterproof and have a daypack over one shoulder. I’ve come 20 miles across mountainous country and tired legs ache as I consider my options.

In this secluded corner of Britain, on the northern edge of Loch Hourn, northwest Scotland, there’s no road, light or soul to be seen; let alone a phone signal. As the clouds drift in, all navigable features are fast disappearing in the gloom.

Time then to wrap myself in a survival blanket and wait for a mountain rescue team to find me and tell me how they feel about my risking mine and others’ lives with my irresponsible jaunt?

Not at all. Despite the fact that to many I would seem to be woefully underprepared and the knapsack I am carrying is little larger than the average family would take on a daytrip rather than the military-sized backpack most hikers in these parts would use, I am confident I have everything I need to see out the night and crack on, safe and refreshed in the morning.

Welcome to ultralight hiking. Unlike conventional hiking (and by 'hiking' I mean journeys of up to 100 miles over several days), this new discipline challenges received wisdom about how best to take on long walks. Rather than packing everything you could conceivably ever need – from bulky torches, blood-plasma first aid kits, tents and spare boots – ultralighters believe the best way to avoid problems is to carry just enough kit to ensure you are safe, but not to overburden yourself with unnecessary adornments and expensive gimmicks.

The approach originated in the US where, from the Pacific Crest Trail in the west to the Appalachian Trail in the east, ultralighters can hike routes of 2,000 miles or more in the summer, averaging 25-30 miles a day. Along the way they cross mountain passes twice as high as Ben Nevis, traverse deserts and sleep comfortably in sub-zero temperatures.

Let’s be clear, however: ultralighting is not about heading off into the back country armed only with a penknife to gut a reindeer and shelter inside it. Neither is it a “burn your possessions and let Mother Nature fold you into her bosom” experience. In August 1992 trekkers found the body of Chris McCandless, one such idealist, in a derelict bus in the Alaskan back country. The tragic tale of his short life is now immortalised in the movie Into the Wild directed by Sean Penn and starring Emile Hirsch.

No. Ultralighting is not an “extreme sport” taken on by those addicted to the thrill of danger. It is about exploring the art of the possible while at the same time cocking a snook at the hi-vis health and safety brigade who would have us take distress flares to the local park.

I discovered an extreme version of it as an infantry officer. I learnt how to carry a lot; find my way (before GPS); and understand the profound psychological benefits of making a cup of tea when everything else is wet and cold. Years after leaving the army, a BBC TV series called Wilderness Walks gave me a glimpse of an alternative. A man called Cameron, a bearded Munro-bagger if ever there was, went walking in the mountains of Oregon with a couple called Ray and Jenny Jardine. They made their own stuff and “left no trace” of their passing along thousands of miles of wilderness trails, in moccasins.

Amid the folksy philosophy lay the simple truth that if you know what you’re doing you need only a fraction of the crap you think you do when hiking.

Most people with a passing interest in the outdoors will admit to having bought overpriced and overspecified kit. At the grizzled instructor end of the outdoor business this is known as “all the gear, no idea”, I wanted to try the inverse approach. Back on my sodden hill, I get a shelter up quickly to get out of the weather, cook and bed down. Despite the fine hikers’ sentiment that “each day is a journey, and the journey itself home”, once you stop moving across country you start to chill fast as sweat goes cold and you stop generating heat.

Ultralighters choose thin layers of man-made fibre for clothing; never cotton, which never dries. Talking of which, there’s nothing worse than chafing and now that rugby players wear Lycra under shorts, it’s acceptable to admit that wearing them on long hikes is essential.

Fleece may be light but it’s bulky. In my pack is a down jacket and a sleeping bag with down on the top side only. Keep it dry and there’s no better insulator, pound for pound, than down. Compressing to nothing, it “lofts” to provide serious warmth. Purist ultralighters make their own down gear by putting a tent up in their living room, climbing in and doing battle with clouds of feathers. Each to their own. Once your pack is light, why add pounds to each foot with stout walking boots? Unless you’re travelling over broken ground with heavy loads (such as climbers approaching an ascent), you’re better off letting your ankles do what they’re designed for and wear good quality trainers. Blisters, too, are less likely if your foot isn’t overheated in thick socks and leather/Gore-Tex-lined boots.

My shelter is an 8ft x 6ft sheet of waterproof nylon stretched between trees with light cord or built as a lean-to with whatever’s available. Constructing it so it sheds the wind and rain is a skill that takes practice, but no zips, poles or flysheets are required. A sleeping mat of “egg box” foam doubles as the back pad within my rucksack. Made from nylon with shoulder straps and a draw-cord closure but no frame, the rucksack has no zips, buckles or pockets.

Eating and drinking enough is essential to covering distances without excessive fatigue or dehydration. One Alaska-based ultralighter takes cylinders of butter rolled in brown sugar to eat on the conveniently frozen trail, but that may be taking things too far. Food of the highest calorific value is the order of the day so nuts and dried fruit are ideal to munch as you go. For hot food, dried meat or vegetables and rice, noodles or oats are best. Water is added to food when you need it and can be made safe with a purifying tab and boiling.

For the ultralighter, cooking is essential, but pressurised gas canisters and jet burners are anathema. Use a “cat stove”, a small converted food tin with holes punched in it for airflow and filled with meths/white spirit. An aluminium windshield protects the wavering flame enough to heat your titanium mug of water to pour into a bag of dried food with enough left over for tea. It takes a little longer but what’s the rush?

Other essential pack items include an LED head-torch; duct tape for fixing torn kit and blisters; minimal wash gear; a medical pack, including foot powder; compass and map; one dry change of shirt, shorts and socks; and a water bottle – plastic not weapons-grade aluminium.

The most important asset in the hills is common sense. To travel light safely, even on well trodden paths in national parks, means you need knowledge of navigation and mountain craft, weather, making a shelter and how to look after yourself and your equipment. Fitness helps: no question. But part of the rationale for ultralighting is to get out there with as little stress on mind and body as possible.

So as the miles roll by with ease you’ll meet others with towering backpacks and trekking poles and instantly feel fitter.

Ultralighting is cheap, too. It offers the belt tighteners an alternative to emitting tons of CO2 by jetting off to lounge by a pool. And the UK has plenty of long-distance paths on offer: some famous (South West Coast Path, South Downs Way, Pennine Way); some yet to be cobbled together by poring over OS maps.

As I flick off the head-torch and contemplate tomorrow’s journey, the shelter bucks in the wind as another rain squall comes in. I’m warm and dry and only now remembering the other essential item for nights like these: the pee bottle.

Disconcerting the first time, but oh so worth not having to get out of your sleeping bag in the night – to say nothing of the hot water bottle fringe benefits. Sorry, girls.