TL;DR
- If your cat fence system is fixed to the boundary (screwed/drilled into posts/panels), it’s not the kind of “temporary” thing that gets you out of fence height rules. Your own install steps literally say: “screw directly into the wood” / “drill… and use the concrete plugs provided.” (Safe Whiskers product page).
- In England, the simple rule is: over 2.0m (most boundaries) = planning permission, and over 1.0m next to a highway (or footpath of such a highway) = planning permission. (Planning Portal).
- Ignore it and you can end up with enforcement, being told to alter/remove it, and it’s an offence not to comply with an enforcement notice. (GOV.UK enforcement guidance).
Are cat fences “temporary” so it does not need to follow the rules?
No. “Temporary” is a marketing dodge when the system is fixed to your boundary.
- The fence rules you’re dealing with are about a gate, fence, wall, or “other means of enclosure.” A cat fence extension bolted to the top of a boundary is exactly that: a means of enclosure. (GPDO wording on legislation.gov.uk).
- Planning arguments about “temporary” don’t boil down to “could I remove it later?” Case law tests used by inspectors lean on size, permanence, and physical attachment — and “permanence” doesn’t mean “forever”, it means it isn’t just fleeting. (Planning Inspectorate appeal PDF).
- If it’s screwed/drilled into posts, it’s physically attached and intended to stay there. That’s not a pop-up structure. Your installation instructions explicitly describe screwing into timber posts and drilling into concrete posts with plugs. (Safe Whiskers product page).
Blunt takeaway: If a company tells people “no planning needed because it’s temporary” while the system is fixed and pushes the boundary over the limit, that’s not something you should rely on.
What are the UK limits? (keep it straightforward)
For England, Planning Portal summarises it like this:
- 1.0m max if it’s next to a highway used by vehicles (or the footpath of such a highway)
- 2.0m max elsewhere
- Measured from ground level
(Planning Portal).
And the legal hook is the GPDO Class A (“gates, fences, walls etc”), covering a “gate, fence, wall or other means of enclosure.” (legislation.gov.uk).
(Scotland/Wales/NI are different systems. Don’t assume England wording applies word-for-word.)
What happens if you don’t get planning permission?
Typical chain: complaint → council investigates → you may be required to fix it.
What matters in practice:
- Councils can take enforcement action if they think it’s expedient.
- If an enforcement notice is served and you don’t comply (and there’s no appeal running), it’s an offence.
(GOV.UK enforcement guidance).
Real consequence: you can end up paying twice — install costs, then cutting it down / reworking it / removing it.
How to pick a system for your back garden
This is how to avoid stepping into planning trouble by accident:
- Measure properly (don’t guess)
- Measure fence height from ground level at multiple points (slopes matter).
- Identify any boundary that’s “next to a highway / footpath” (the 1.0m zone). (Planning Portal).
- Decide: stay compliant or plan to apply
- If you can keep the overall boundary at or under 2.0m (or 1.0m where relevant), do it.
- If your design needs over those limits, assume you’ll need permission.
-
Prefer “inward overhang” over “just make it taller”
A good cat fence works by making the top awkward to climb and impossible to vault, not by turning your garden into a 2.4m perimeter. -
Be honest about fixings
If you’re screwing/drilling into posts, treat it as a proper alteration (and get landlord/freeholder permission if you rent/leasehold).
Best cat fence options (with planning in mind)
1) Fence-top systems designed to work around the 2.0m limit
Best for: most typical UK gardens.
Why: containment via an inward overhang, not extreme height.
- Safe Whiskers Cat Fence: fixed install (screw into timber posts / drill concrete posts + plugs). (Safe Whiskers product page).
2) Roller/rotating toppers (minimal added height)
Best for: when your fence is already close to 2.0m and you want the smallest possible “height penalty.”
Watch-out: measure — “small” can still push you over.
3) Catios / enclosed runs
Best for: renters or shared boundary drama.
Why: doesn’t extend the boundary fence height (though very large structures can still have their own planning considerations).
4) Very tall perimeter systems (2.2m+)
Best for: only if you’re willing to do planning properly.
Planning reality: if it’s fixed and over the limit, don’t buy the “temporary” line. (Planning Portal).
FAQs
Does a cat fence extension count as fence height?
If it increases the boundary’s “means of enclosure”, assume yes. That’s the wording used in permitted development. (legislation.gov.uk).
Is “temporary” a valid excuse if it’s screwed into the fence?
No sensible person should rely on that. Physical attachment + intended ongoing use works against the “temporary” argument. (Planning Inspectorate appeal PDF).
What if my fence is already over 2m?
Planning Portal flags that if an existing fence already exceeds the limit, you can’t just increase it further under permitted development. (Planning Portal).
What if I install first and ask later?
You might be invited to submit something retrospectively, but enforcement is still on the table, and non-compliance with a notice is an offence. (GOV.UK enforcement guidance).