Spending 18 days with 20 kilos on your back, a machete in your hand and bears and bamboo shoots for company isn't many people's idea of a good time. But then no-one ever claimed exploring the unfrequented corners of the world was easy.

That's certainly the philosophy of Lochcarron mountain guide Martin Moran. Later this month he and four companions from the UK and India, assisted by New Zealand based mountain guide Brede Arkless will be cutting loose from the outside world and stepping into the unknown.

Their aim is to make the legendary crossing between the Hindu temples of Badrinath and Kedarnath in the Garhwal region of the Indian Himalaya. History recalls that the crossing has only been made once before, by the great mountaineers and explorers Bill Tilman and Eric Shipton in 1934.

Tilman, Shipton and their Indian porters expected a two-day crossing, but spent two weeks hacking their way through dense forest, competing with bears for a diet of bamboo shoots, when their food ran out. Two Bengalis who attempted to repeat the route in 1986 disappeared without trace.

Moran explains: ''I first read about Shipton and Tilman's epic in an extract from one of Shipton's books. Entitled ''The Bamboo Valley'' it was one of those eye-opening reads where you just read this story which you don't expect to go anywhere special and suddenly it turns into this big epic and leaves an incredible impression.

''But I'd never traced their route on the map until I started visiting the area on mountaineering expeditions a few years ago. Getting maps to the area gave the opportunity to actually pinpoint the valley Shipton and Tilman travelled down. It then became an idea to try and repeat their journey.''

What spurred Shipton and Tilman into making the crossing in the first place was the old Indian legend which recounted how a priest at one temple managed to perform a puja, the Hindu religious ceremony, in the morning and cross to the other temple to perform a puja in the afternoon.

The distance between the two temples is about 30 miles as the crow flies, but the journey entails a long trek up the heavily crevassed Satopanth glacier from Badrinath to a pass at 52000m. From there a descent down a steep icefall and across a glacier leads into the steep sided Markanda Valley.

In 1934, bad weather kept the Shipton, Tilman team hemmed in the valley, complete with epic river crossings and thick jungle, until they finally popped out of a gorge at the bottom, alive, emaciated and about 25 miles south of Kedernath.

However, Moran thinks that once on the high pass, other route options may allow them to keep out of the forest so they can climb out of the valley again and cross two smaller valleys, to complete the fabled route direct to Kedernath temple.

The team plan to take six or seven days climbing up to the pass but they know that deep snow could make this bit of the journey hard work. From the pass there will be the icefall to negotiate and 10 days to bushwhack out to Kedernath.

Moran continues: ''In 1935 Shipton and Tilman found the icefall difficult and if the glaciers have retreated since then as we would guess they have, that's not going to make things any easier. Shipton mentions a rock buttress on one side which they had to avoid because they had no equipment, but we might be able to abseil down it instead.

''After the col we are really on our own. It's a bit daunting but that's how it used to be in the old days. Personally, once we get down the icefall I'll feel pretty good, because the rest of the trip's certainly going to be extremely difficult.''

In India, the expedition will be joined by an unexpected extra member in the form of John Shipton, son of Eric Shipton. Although not a mountaineer himself, Shipton hopes to travel with the team as far as he can to the pass, in the hope of repeating at least some of his father's epic journey.

The team will not carry any form of communication with the outside world, save a transistor on which they hope to receive weather forecasts and a GPS navigation system to determine their progress on the map.

''It's hard to know what's in the Markanda

Valley,'' concludes Moran. ''The map marks a hot spring, which suggests somebody's been in there to know that it exists. There's also the remotest possibility that there still might be tiger in the valley.''

The final word on their journey must go to the reported words of Shipton and Tilman, probably apocryphal, but entertaining none the less. On the final day they climbed a ridge and glimpsed a village. The porters were joyous. Tilman

greeted the sight with a dry comment of the sort for which he was well known: ''We shall be down for tea,'' to which Shipton simply stuttered: ''Thank heaven for that.''