This is the ideal but is it really allowed? Unfortunately, not. In most European countries you are not allowed to camp in open country. Only in the more northern countries, such as Sweden and Norway, is there a general right to roam.
Yet there is still a chance to enjoy a wilder experience. In Denmark it is generally prohibited except at designated ‘nature camps’. In Germany, Ireland and Scotland it is permitted, subject to certain conditions. Camping above the tree line in open country is often overlooked in England and Wales. But in Mediterranean countries, Spain, France and Italy, it is generally forbidden and wild campers are liable to be fined.
Subject to certain conditions, bivouacking (camping from 7pm to 9am) may be permitted in French and German national parks and in the Alps. If you are unable to reach the next campsite or hut in time then you have a chance to put up your tent before nightfall (please check rules in advance).