Fidler v First Secretary of State and Reigate and Banstead Borough Council [2004] EWCA Civ 1295
Fidler mixed use is an important Court of Appeal judgment on how a planning unit with several commercial activities can change materially over time, even where the broad descriptions of those activities remain much the same.
It also gives a clear warning about section 173(11) under-enforcement: an enforcement notice does not accidentally grant permission for every other breach the council happened to know about.
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- Neutral citation
- [2004] EWCA Civ 1295
- Court
- Court of Appeal (Civil Division)
- Judgment date
- 12th October 2004
- Judge
- Lord Justice Brooke, Lord Justice Buxton and Lord Justice Carnwath
- Case number
- C3/2003/2206; C3/2003/2207
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What Fidler mixed use decided
The case concerned Honeycrock Farm in Surrey, where a single planning unit contained agriculture alongside a range of storage, haulage, contracting, workshop and other commercial activities.
The Inspector found that over the relevant ten-year period the land area in commercial use increased, the main buildings were enlarged and substantially altered, outdoor storage expanded, newer occupiers generated more traffic and the overall character of the activity changed.
The Court of Appeal held that he was entitled to find a material change of use when those changes were looked at together.
A mixed use can change without acquiring a new label
The court confirmed four familiar planning principles. The decision-maker identifies the appropriate planning unit; that unit may contain a composite or mixed use; a change in intensity can alter the character of the use; and materiality is a question of fact and degree.
The Inspector therefore did not have to invent a completely different description for the use at the beginning and end of the period. The question was whether its character had changed materially.
The Use Classes Order does not split a mixed use into protected components
Mr Fidler argued that individual B1, B2 and B8 activities should benefit from the rule that movement within the same use class is not development.
The court rejected that argument. The relevant land was in a mixed use and there is no mixed-use class. Replacing one component with another activity in the same use class does not prevent the character of the mixed use as a whole from changing materially.
Extending the activity onto more land can matter
The commercial use had expanded onto adjoining land. The Court of Appeal held that whether such an extension creates or alters a planning unit, and whether it contributes to a material change of use, is again a matter of fact and degree.
For a fuller explanation of this concept, see our guide to planning units, ancillary and incidental uses.
Section 173(11) does not legalise unrelated breaches by accident
An earlier 1995 enforcement notice had targeted an engineering contractor’s depot but not the other commercial activities then taking place. Mr Fidler argued that, once that notice was complied with, section 173(11) gave deemed planning permission for the other uses.
The court rejected that argument. Section 173(11) applies to development or activities within the breach identified by the particular notice which the notice could have required to cease or remove but did not. It is not enough that the council could have served a differently drafted notice dealing with other breaches.
This is the principle behind our guide to under-enforcement and deemed planning permission.
An enforcement notice can sometimes set limits rather than require everything to stop
The court also drew attention to ground (f) and section 173(5)(d). In a fluctuating mixed use, an appellant may argue that requiring complete cessation goes further than necessary and may propose clear limits on an activity instead.
The burden is on the appellant to put forward a workable alternative. See our main planning enforcement section for the wider enforcement framework.
Read the full Fidler 2004 judgment
The full Court of Appeal judgment is held in the Planning Geek case law library. Gold Members can open the protected PDF below.
Fidler Mixed Use Case Law Page Updated: 9th September 2026