If you really want to feel you’re in the great outdoors, you should try wild camping. It’s more exciting, it’s free and you really feel part of the countryside. It is generally only legal in England and Wales with the prior permission of the landowner, though in most cases, if you ask nicely you probably won’t be refuesed.
Follow these rules: keep out of sight and away from livestock, do not build open fires, do not camp in large groups, respect the environment, stay for one night only, and follow the wild camper’s mantra: “pitch late, leave early.”
While you should also follow the above rules, things are easier in Scotland. The Land Reform (Scotland) Act 2003 makes wild camping legal in most cases as long as practised away from homes and roads.
The Guardian has this excellent article on wild camping. It gives recommendations, in addition to much of Scotland, for Dartmoor, The Berwyn mountains, North Wales, South Downs and The North Pennines.
For Scotland see: the Scottish Outdoor Access Code