Living Full Time
Can you live full time in your camper or motorhome? No. The law does not recognise the situation where someone doesn't have a permanent physical address being a physical property, but there are certain allowances. Don't forget to read our The Law and You article.
Some Definitions, from the Caravan Sites and Control Development Act 1960; The structure must not measure more than 20m in length, 6.8m in width, and the overall height of living accommodation (measured internally from the floor at the lowest level to the ceiling at the highest level) must not be more than 3.05m.
Given that, and that its not uncommon to be 'away' from your fixed residence whilst in a motorhome or caravan, how does this relate to service of penalties and other legalised extortion ? As you may have already anticipated, if you're not at your fixed address, even on holiday for example and you miss the fixed penalty notice, or intention of prosecution, tough. You can attempt to argue that you were away, but there's no lawful excuse to not responding within the time limit. At the time of writing, for some offences, a county court judge is required to arrive at the penalty, who with the correct evidence may be persuaded to mitigate your failure to respond but it depends specifically on the judge, time of day, and whether his hemorrhoids are playing up. We are already seeing legislation changed so that penalties can be extorted without the need of a county court judge, because (a) they are expensive and have better things to do, and (b) the number of automated extortions is increasing exponentially. At some point, all these automated fines and penalties will be extorted without any right to appeal or judgement, if we let it - and we will. The point is, whoever you use to receive your mail as your nominated fixed abode, make sure they open the post and alert you swiftly of anything containing the words 'penalty' and 'force'.
On your own land
You do not need planning permission, nor any sort of licensing to park your camper or motorhome on YOUR own land, providing it is at most being used as an annex of your home. You are however restricted from Renting it out for money. The local council can however interfere with this in what is called Article 4 directions for no good reason so you will need to check for this.
If on the other hand this is going to be your main dwelling, then you will need planning permission if it is so for more than 28 days, the fine (tax) for not having planning permission is £2500 for what that's worth.
There are 'loopholes' but they aren't very elegant and kinda on the verge, but technically if you can divide your land up into plots, and register each plot with a different family member, then technically you can move your vehicle between these plots every 28 days, providing you pay £1 to each 'landholder' for rent. I know, stupid it is, but that's what the law says.
On a Licensed Campsite
The License (Planning permission) obtained by a camp site limits your visit to 28 days (21 days in certain circumstances), after which time you must leave the site for at least 48 hours before returning, and then you can stay another 28 (or 21) days.
This might seem like a good option, but site owners are of course weary of the rules since they are the ones inline for a fine and possibly withdrawal of their permission should they break the rules, so consider moving between several sites staying only 21 days to be safe in each, and everyone should be happy with that, but do keep a record of when and where and keep the receipts showing this so you can back up your movements should a site owner receive local authority harassment.
On Agricultural Land
Well, IF you are working on the land AND its seasonal work, then under the Town And Country Planning (General Permitted Development) order 1995, AND, the Caravan Sites and Control Development Act 1960, Paragraph 7 which states, that for agricultural workers a site license shall not be required for the use of agricultural land as a caravan site for the accommodation during a particular season of a person or persons employed in farming operations on land in the same occupation. Paragraph 8 is the same but for forestry workers. Great right? Well, again no, the local authority can at their sole discretion poopoo this idea if they think its not being used as described, and a long and costly legal battle will surely follow, which no one wants.
Public Houses (pub's)
Its becoming increasingly common these days for public houses to afford some car park for the purpose of overnight stays. They do this often with planning permission which limits this to 5 units and 2 days (in most cases), so you can't stay there permanently, but you can rotate between a series of pubs (at least 7) staying one night a week at each successfully, given that no one complains, and you're happy to provide patronage at each pub, which most will expect.
On Private Land (not yours)
Up until the start of 2022, you could park on private land and be guilty of civil trespass, not a criminal offence which then required the landowner to apply to the courts for an eviction order and all the joy that goes with that lengthy and costly process. Since the landowners are also likely politicians, friends of politicians or party donors, Parliament created a new law “Police, Crime, Sentencing and Courts Act 2022” which provides the usual excessive powers such as 3 months in prison and forceful removal. If you're on private land and asked to move by the Police, then just do it and do not return.
Car Parks and Roadside
You cannot live in a car park, nor at the side of the road full time, in the same place, but you can of course park overnight in any car park (providing the council aren't hostile with signage) and in any layby (again providing the council aren't hostile), but not for more than a couple of nights in the same place before a window twitcher is bound to notice, make a complaint and some pencil neck is bound to show up at some point and ask you to move on - and you MUST move on if the Police request it, even if you're in the right or you'll be committing a criminal offence worthy of arrest, and they can leverage the Criminal Justice and Public Order Act 1994 to seize your vehicle.
Real Life
Most of the people I know who live full time, do so by rotating a series of places on a continuos basis, and being aware of the environment, but unfortunately with the recent explosion in popularity, many councils are now becoming increasingly hostile to travellers, putting up height barriers and signage (mostly illegal) to restrict you. There are some counties worse than others but its only going to get worse I'm afraid. Eventually, laws will be passed preventing anyone from living in a mobile vehicle with the usual excessive penalties to force compliance. This is the country we live in unfortunately - Try Europe, the USA, Canada, Scandinavia, actually anywhere else for a far more amenable attitude.