This particular tarn is the largest of the three Blea tarns named in the Lake District. The tarn itself is relatively easy to reach, both from Dob Gill (Thirlmere) or from the lovely hamlet of Watenlath. The big 'however' for this tarn is its unfortunate location, right in the middle of the notoriously boggy central ridge. An place with an acceptable reputation for being the boggiest area in the Lake District, and not somewhere you want to stray into during poor visibility.
At close quarters the tarn may, for the more difficult to impress visitor, look more than just a little bit unattractive. If on the other hand you happen to be ascending Ullscarf via the Standing Crag route, then you'll pass several fine vantage points where you may be inclined to modify a somewhat less than favourable opinion of the tarn. Particularly from Standing Crag itself where you're offered a spectacular view of the tarn and the fells to the north and west.
Having visited this tarn in almost every weather imaginable, from scorching hot summer days to rain, snow and frost in winter, I have to admit that several bad experiences have educated me to the fact that this is an area best kept for the middle of a drought or during a period of hard frosts.