When does a bivi bag become a tent?

The dividing line isn’t clear but I’d say the Bivi 1P is somewhere on it, neither one thing or the other. It does have poles – two curved ones at the head and a short upright at the rear – and guylines but it’s still so low and narrow that the fabric touches your sleeping bag. The poles provide a smidgeon of head room but not enough for me to lie propped up on one elbow.

A small amount of gear can be stored inside. The entrance zip curves down from the high point along one side so when it is open there is plenty of ventilation and a good view. The fabric is quite breathable and there’s a protected small mesh panel at the apex for ventilation. The Bivi 1P can be pitched quickly – just six pegs are needed.

The weight is similar to the lightest tents, which are much more roomy – though also much more expensive. As a shelter it will keep you dry but I’d rather have a basic bivi and a tarp.