There's all kinds of camps, (I would think they have them in the UK as well) for different interests, from music to religion to writing, to all the various sports, etc. It's an American summertime tradition.
We have camp sites for families or just groups of people to use for holidays. So have additional facilities but many are just a field and washing facilities and possibly a shop to buy food and a social club for evening entertainment.
Also organizations like Guides and Scouts go camping. This weekend which is Spring Bank Holiday Weekend in Britain many Brownie, Cubs, Scouts and Guides will be camping. In fact a lady from work helps run a Scout group and she has borrowed the company van to transport a lot of the equipment for the weekend camp.
I have been camping myself twice both as an adult at a folk festival (Fairport Convention). Here a friend is pitching her tent.