What is a bug out bag?

A bug out bag is simply a bag that survivalists keep permanently packed and ready to go. This is a sort of escape kit and in the USA often contains outdoor survival equipment. The contents of the kit will vary according to the nature of the perceived threat. Britain is more densely populated than the USA and so there is far less countryside to escape to.
My own bug out bag contains a few outdoor items along with my documents. The remainder of the space is taken up with lightweight food and drink. In fact I suspect that my bug out bag will never be used for this purpose as I would probably wait out most emergencies at home.
Nevertheless I have chosen each item carefully for multiple uses. My bug out bag is a useful camping kit, took kit, and general resource.