This has long been one of my favourite walks because it is lovely to look at, is full of natural history and has a haunting name. The geometric shape of this 70 acre (28 hectare) lake has led to two suggestions. Firstly, that it was built by the monks and secondly it should not be regarded as a lake but as a tarn. With regard to the second point, experts continue to argue about it, but to be honest who cares? To me it is just a beautiful place and well worth a gentle stroll around it. The lake was certainly used as a fish pond by the Cistercian monks of Furness Abbey and there is an amusing story which tells us that the volume of the water equated with the volume of ale consumed by the monks in a year. Some thirst!

There is, no doubt however, that it was naturally formed and was once part of the much larger Ullswater. The two became isolated as a result of silt being flushed down by rain from the surrounding fells. The surrounding area became stablised as Brotherswater, and is now two miles south of Ullswater and at the foot of the awe-inspiring Kirkstone Pass.

Route: From the road leading over the Kirkstone Pass, follow the A592 into the village of Hartsop and there is a car park at Cow Bridge and from which the walk starts.

Map Ref: OS Explorer OL5

Grid Ref: for car park 400 135

Length of walk: 3.5 miles

1 From the car park move into one of the most attractive oak woods in the whole of Cumbria. Turn left and continue through the woods with Brotherswater on the left. At this time of the year oak woodlands are a delight and acorns are beginning to develop. The old word for the oak was acc and accounts for place names such as Acton and Accrington. There are far too few oak woods left these days but this one is an absolute stunner. Do not rush this section as it provides shelter in wet weather and shade in the heat of the summer.

2 As the woodland is passed, approach a track with Hartsop Hall on the left. This is a building with a fascinating history. Parts of this date to the 16th Century but the de Lancaster family made lots of additions in the 17th Century. For a while Lord Lonsdale, whose name is associated with the Lonsdale belt in boxing, lived in the hall for a while. From the hall bear to the right and then take a left turn, cross a footbridge over a stream and then through a gate into a field.

3 Follow the obvious grassy track to reach a slab bridge over Dovedale Beck and at this time do not rush but look for evidence of a prehistoric settlement around Dovedale. Keep Kirkstone Beck on the left. This is in complete contrast to the oak woodland and some of the earthworks stand almost ten feet high and a view from the settlement reveals spectacular mountain scenery.

4 Pass through the settlement and then turn sharp left and cross another stream via a wooden footbridge. This is called Caiston Beck and is an excellent place to watch two beautiful resident birds, the grey wagtail and the dipper. Continue onwards to reach the A592 and for a short distance use the footpath alongside the road to reach a campsite on the left and the old Brotherswater Hotel on the right.

5 In front of the Old Inn bear first left and then right to approach a permissive footpath off to the left. This follows a sunken path running parallel to the road. the track is always damp and during periods of heavy rain or snow melt, it can be impassable. At such times there is a wide verge alongside the A592.

6 The track passes alongside Brotherwater to the left and leads to the village of Hartsop. The name indicates that this was once and still is a place where deer are found. Here are fields which are kept moist by the waters of the well named Pasture Beck. Here are the remains of an old water powered corn mill, a 16th Century drying kiln and the cottages have spinning galleries. These were designed to provide the maximum daylight in which to work before the days of electricity. Return to the Cow Bridge car park.

NB: Restrictions on space mean that this article provides a general summary of the route. It is advisable for anyone who plans to follow the walk to take a copy of the relevant Ordnance Survey map .