Film Unit Bases, Trailers and Caravans

A film unit base can create a planning problem even when the filming location itself looks straightforward. Production offices, artist trailers, make-up and costume units, catering, welfare facilities, generators and parking can amount to a substantial temporary use of land.

The caravan issue is particularly important. Since the 2023 changes to Class B, that general 28-day temporary use right cannot be used for the siting of any caravan apart from a narrow festival exception.

Film-industry labels are not decisive. A large artist or welfare trailer may satisfy the statutory caravan definition even if nobody sleeps in it, while an equipment or generator trailer may not. The design, adaptation and mobility of the actual unit matter.

Does a unit base need planning permission?

Not every small unit base will necessarily amount to development. As with the filming itself, the question is what the temporary occupation does to the character and use of the land and whether any operational development is involved.

A few production vehicles parked briefly on an existing commercial yard are very different from a field occupied by dozens of trailers, temporary welfare facilities, generators, lighting, trackway and heavy vehicle movements for several weeks.

Where the use is development, the available permitted development route must be checked against the actual units proposed.

Why caravans are a Class B problem

Class B can normally permit a temporary use of land for up to 28 days in a calendar year, but the current wording excludes the siting of any caravan except a motor vehicle designed or adapted for human habitation which is sited in connection with a festival.

That makes the classification of production trailers important. A unit base is not safely within the 28-day right merely because everybody describes the vehicles as trailers.

What is a caravan in planning law?

The GPDO relies on the statutory definition in section 29 of the Caravan Sites and Control of Development Act 1960, read with the twin-unit provisions in section 13 of the Caravan Sites Act 1968.

Broadly, a caravan is a structure designed or adapted for human habitation which has the required quality of mobility. The test is not whether somebody currently sleeps in it, whether it has wheels on show or what the hire company calls it.

An artist trailer with living facilities is an obvious candidate. A make-up or wardrobe unit may be fact-sensitive. A camera, grip, power or equipment trailer with no human-habitation design may be different.

The key caravan cases

Planning Geek hosts the main authorities in our Case Law Library.

• Wyre Forest District Council v Secretary of State confirms the importance of the statutory definition rather than the everyday appearance of a caravan
• Carter v Secretary of State deals with mobility of the structure as a whole and a four-section park home which required dismantling before transport
• Bury Metropolitan Borough Council v Secretary of State shows why a finding that a structure is mobile needs an evidential basis

Those cases are not film-industry decisions, but the same statutory caravan test applies when a production unit is being classified.

Can Class E help with a unit base?

Class E does not contain the same express caravan exclusion as Class B. It allows temporary structures, works, plant and machinery required in connection with commercial filmmaking and its definition of a filming period includes preparatory or related activity.

That does not mean every off-site production base is automatically authorised by Class E. The use of the particular land, its relationship to the filming and all of the Class E limits and exclusions still need to be assessed. If Class E is being relied upon, prior approval is mandatory before the new filming period starts.

Class E also excludes use of the land for overnight accommodation, so a unit base cannot simply be treated as an accommodation site under the filmmaking right.

Hardstanding, trackway and temporary works

A unit base can involve more than a change of use. New hardstanding, excavation, drainage, substantial trackway, lighting columns, compounds or other works may themselves need planning consideration.

Temporary does not always mean permitted development. The nature of the works, how they are installed and whether the land is restored all matter.

Highways, neighbours and operating hours

Unit bases generate repeated vehicle movements, servicing and activity at the beginning and end of long production days. Access, parking, noise, generators and lighting can therefore be more important to the planning assessment than the filming taking place elsewhere.

Separate parking, highway or road permissions may be required. See our filming permits guide.

What I would ask for

• a plan showing the filming location and any separate unit base
• the proposed number of production and filming days
• a schedule of all trailers, motorhomes, welfare and equipment units
• manufacturer information where caravan status is uncertain
• details of hardstanding, trackway, lighting, generators and drainage
• vehicle numbers, access arrangements and operating hours
• any proposed overnight accommodation

That information lets us test the planning route rather than guessing from a photograph of a very large trailer.

Filming and photography planning resources

Location filming can involve planning permission, permitted development, private or public land permissions, roads, protected sites, production bases and drone restrictions. Use the guide which best matches the issue you are dealing with.

Film Unit Base Page Created: 11th October 2026