Caravans, mobile homes and annexes in a garden

Putting a caravan in your garden for a relative to live in almost always needs planning permission, even though the caravan itself is not a building and stationing it is not building work. The permission is needed because the use of the land changes. A caravan used for storage, as a hobby room or by members of the same household is normally incidental to the dwellinghouse and attracts no control at all. A caravan occupied as an independent home creates a second dwelling on the plot, and that is a material change of use.

Everything else follows from which of those two situations you are in, so it is worth being honest about it at the start rather than after an enforcement officer knocks.

When stationing a caravan is development

Section 55 of the Town and Country Planning Act 1990 catches building operations and material changes of use. A caravan as defined by the Caravan Sites and Control of Development Act 1960 is a structure designed or adapted for human habitation that is capable of being moved from one place to another, so simply placing one on a hardstanding is not a building operation.

That leaves the use question. If the caravan is used for purposes incidental to the enjoyment of the house, nothing has changed in planning terms. Garden storage, a workshop, a playroom, a place for visitors to sleep for a fortnight in the summer: none of that alters the use of the land.

Two things can pull the caravan back into the definition of a building. One is immobility. A twin-unit structure craned in, bolted to a plinth, with its wheels and towing gear removed and the underside bricked up, may no longer be capable of being moved, in which case it is operational development and needs permission in its own right. The other is size. The Caravan Sites Act 1968 sets dimensional limits for twin-unit caravans, currently 20 metres in length, 6.8 metres in width and 3.05 metres internal height. Exceed them and the structure falls outside the statutory definition.

Incidental, ancillary and separate occupation

These three words do different jobs and conflating them causes most of the trouble.

Incidental use is the test in Class E of Part 1 of Schedule 2 to the General Permitted Development Order, which allows outbuildings required for a purpose incidental to the enjoyment of the dwellinghouse. Primary living accommodation, and in particular sleeping accommodation forming someone's home, is generally not incidental, which is why a self-contained annexe is a weak candidate for Class E rights. Class E also excludes buildings designed as separate living accommodation outright.

Ancillary use is broader. A granny annexe occupied by a dependent relative who shares the household, eats in the main house and has no separate entrance or kitchen may be ancillary to the single dwelling, so the planning unit is unchanged. The same building with its own kitchen, its own front door, its own garden and a tenancy agreement is a separate planning unit and a second dwelling.

Separate occupation is the line that matters. The question is not who lives there but how independently they live. The same analysis applies to garden buildings used for work, which is set out in the note on garden offices and the separate planning unit problem.

The separate dwelling question

Officers look at a familiar set of indicators and weigh them together.

No single factor decides it. A full kitchen and a separate entrance together are usually enough for an officer to conclude that a second dwelling exists, and a separate council tax band is awkward evidence to argue against.

Councils also look at whether the annexe could function independently if the family relationship ended. That is why permissions for annexes are so often conditioned.

Site licensing under the caravan legislation

A separate regime runs alongside planning. Land used as a caravan site normally needs a site licence from the district council under the 1960 Act, and the licence can only be issued where planning permission for the use exists.

Schedule 1 to the 1960 Act lists exemptions, and the first of them covers use of land within the curtilage of a dwellinghouse where the caravan use is incidental to the enjoyment of that dwellinghouse. So a caravan parked beside the house for storage or occasional family use needs neither permission nor a licence. Once the caravan becomes someone's permanent home, the exemption falls away and both the planning permission and the site licence come into play.

Other Schedule 1 exemptions cover travelling people stopping for a night or two, building and engineering sites, seasonal agricultural and forestry workers, and certain exempted organisations. None of them is a route to a permanent garden annexe.

Utility connections and what they signal

What you connect tells the council what you intend, and it is the evidence most often used against applicants.

A spur from the house consumer unit, a water feed from the garden tap and a shared drainage connection all read as ancillary. A separate electricity supply with its own meter and its own account, a new foul connection applied for in the occupier's name, a separate broadband line and a letterbox with a different house number all read as independent. So does a new dropped kerb and a separate parking space.

Drainage deserves a thought of its own. Connecting a caravan to the public foul sewer usually needs the agreement of the sewerage undertaker, and on an unsewered site a package treatment plant or septic tank brings the Environment Agency general binding rules into play.

Conditions councils attach to annexe permissions

Where permission is granted, expect conditions designed to keep the annexe tied to the main house.

1. Occupation restricted to a named relationship, commonly a dependent relative of the occupiers of the main dwelling, or to use ancillary to the main dwelling.
2. A requirement that the annexe is not sold, let or otherwise disposed of separately from the house.
3. A prohibition on subdividing the curtilage by fences, walls or hedges.
4. For a caravan, a requirement that it is removed when the need ceases, sometimes with a fixed expiry date.
5. Restrictions on further extension or on inserting additional cooking facilities.

These conditions are the price of permission and they bite on resale. A buyer's solicitor will find them, and a lender may treat a conditioned annexe differently from a house with a spare bedroom. The floor area limits that govern ordinary garden outbuildings are a separate matter, covered in the explanation of the 50 per cent curtilage rule.

Evidence for a lawful development certificate

Where the caravan or annexe is incidental or ancillary in fact and you want that recorded, apply for a certificate of lawfulness of existing use or development under section 191 of the 1990 Act, or for a proposed use under section 192. A certificate is the only formal way to confirm that works or a use are lawful.

The evidence that carries weight is documentary and dated. Utility bills showing a single supply. Council tax records showing one band. Photographs showing a shared garden with no dividing fence. A statutory declaration from the occupiers describing how the household actually works. Plans showing the internal layout, including the absence of a second kitchen.

If the caravan has already been in independent residential use for a long period, immunity from enforcement may be in play. The Levelling-up and Regeneration Act 2023 replaces the former four-year immunity period with a single ten-year period for breaches in England, so check the current commencement position and the transitional arrangements on gov.uk before relying on either figure.

For an application rather than a certificate, the supporting case is usually a short planning statement addressing the need, the relationship to the main dwelling and the acceptability of the siting, with a site plan showing the shared curtilage. Enter your postcode on PlanScope to see which documents a garden annexe proposal on your plot is likely to need.

This is general guidance, not legal advice. A lawful development certificate under section 191 or 192 is the only formal way to confirm that works or a use are lawful, so check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.