BEINN Mhanach is not the most loved of Scottish mountains.

Irvine Butterfield, in his High Mountains of Britain and Ireland, describes it as a tedious lump, and most Munro-baggers have probably cursed it because of its awkward situation.

This Monk Hill, so called because some ancient clerics once founded a monastery at its foot, is placed within the tight clench of the four Bridge of Orchy Munros - Beinn Dorain, Beinn an Dothaidh, Beinn Achaladair and Beinn a' Chreachain, the hills that form the Great Wall of Rannoch, the boundary between the old Pictish kingdom of Alba to the east and the Dalriadic kingdom of the Scots in the west. If you imagine these four mountains forming a tight curve, then Beinn Mhanach lies isolated within that curve, its only point of attachment a 600m col below the south-east slopes of Beinn Achaladair.

My first two ascents of Mhanach treated the hill independently from the others. On one memorable excursion a friend, Taff Bowles, and I skied in from Bridge of Orchy over the bealach between Beinn Dorain and Beinn an Dothaidh. We enjoyed a good run of firm snow down to the head of the Auch Gleann from where we had to climb on skins up to the head of Gleann Cailliche and then up to the summit. The descent was a superb one on good snow all the way back to Bridge of Orchy.

My second ascent followed the Auch Gleann from the A82 past Ais-an-t-Sidhean, a ruin that was once the home of the great Celtic bard Duncan Ban MacIntyre, fair-haired Duncan of the Songs.

The ruin is now used as a sheep fank, an ironic change of use since MacIntyre hated sheep, blaming them for the chaos and turmoil of the highland clearances. His poem, Oran nam Balgairean, the song of the foxes, explains his loathing for the beasts, "My blessing be upon the foxes, because that they hunt the sheep, The sheep with the brockit faces that have made confusion in all the world."

While these routes to Beinn Mhanach are interesting, they are both linear, out and back the same way, so with my mate John desperately wanting to tick off his "odd" remaining Munros, we tackled Mhanach from another attack point, and at the same time gathered in Beinn Achaladair and Beinn a' Chreachain as well, a good day of about 12 miles with more than 5000ft of climbing.

We chose Achallader Farm as our starting point, just off the A82, close to the foot of Loch Tulla, a modern farm with a ruined castle in its front yard. It was here that Black Duncan of Cowal, Campbell of Glenorchy, built one of his seven castles and it was here that Robert Campbell of Glenlyon rested as he made his way north to Glen Coe in the days before the 1692 massacre.

There was little rest for us as we climbed up the length of Coire Achaladair in the warm sun. From the bealach at the head of the corrie, we traversed the grassy southern flank of Beinn Achaladair to the col at the head of Gleann Cailliche, from where we managed to climb to the summit of Beinn Mhanach and back in about an hour.

Now it was time to start work, up into Coire nan Clach of Beinn Achaladair and a scramble up rocky slopes to the exposed summit. What an airy perch this is with superb views across the flat Rannoch Moor to the mountains in the north, dominated by the crouching profile of Ben Nevis. A magnificent high-level promenade took us east to the stony hump of Beinn a' Chreachain, before a long grassy descent dropped us down to the West Highland railway and the track back to the farm.

In the late afternoon sun the Wall of Rannoch showed us its best face, picked out by the shadows and light. Presenting only broad, dull shoulders to the carborne tourist on the A82, I remembered once again that so many of these hills jealously guard their finer features for those who would seek them.

FACT FILE

Map: OS Sheet 50 (Glen Orchy)

Distance: 12 miles/5,000ft ascent

Approx time: 8-10 hours

Start/finish: Achallader Farm

Route: From the farm, head S along a track, over the railway and up Coire Achaladair. Climb to the col at the head of the corrie then traverse the S slopes of Beinn Achaladair to the bealach at the head of Gleann Cailliche.

From here climb to the col between Beinn a' Chuirn and Beinn Mhanach, then walk E to the summit.

Return to the head of Gleann Cailliche, and climb steep slopes in a NW direction to the summit of Beinn Achaladair. Descend E along the corrie rim and descend to the col at 800m. Follow the broad ridge over the flat top of Meall Buidhe and then up the stony slopes of Beinn a' Chreachain.

Descend by the steep NE ridge and once the crags are avoided, turn WNW to descend grassy slopes, past the Lochan a' Chreachain, past scattered birches and through the pines of Crannach Wood. Cross the railway by a footbridge and take the track by the Water of Tulla back to the farm.