Are grey squirrels pests? The UK guide to damage, risk, and what to do next
⚠️ Guidance only: this article is general information, not legal advice. Always follow UK law and site safety rules. If you’re dealing with trapped animals, roof access, electrics, firearms or protected species, don’t improvise — get competent help.
Are grey squirrels pests? In the UK, the honest answer is: they can be — not because they’re “bad”, but because they cause expensive damage to trees, can get into buildings, and play a major role in the decline of red squirrels. On rural properties, farms and estates, grey squirrels are often treated as a serious management problem rather than a minor nuisance.
This guide explains what damage grey squirrels actually cause, why it matters, what the UK legal position means in practice, and when calling a pest controller is the smart move.
Why grey squirrels cause bigger problems than most people realise
Grey squirrels are highly adaptable. They thrive around people, exploit easy food, and use rooflines, trees and hedges as “motorways”. That’s why small issues often escalate: once a squirrel learns a route into a loft, or a woodland patch becomes a feeding ground, it tends to repeat.
They also have a disproportionate impact on native wildlife. Grey squirrels are resistant carriers of squirrelpox virus, which is typically fatal to red squirrels and accelerates red squirrel decline where it’s present.
Grey squirrel damage to trees: bark stripping and long-term loss
The biggest “hidden” cost of grey squirrels is bark stripping. They strip bark from trees (often in spring and early summer), which can:
- kill or weaken trees (especially younger trees)
- open the tree to disease and decay
- ruin timber quality and value
- set back woodland creation and shelter belts
Official guidance puts the cost of grey squirrel bark stripping damage in England and Wales at at least £37m per year when you account for lost timber value and mitigation/replacement.
If you own land, manage an estate, or rely on woodland margins for shelter, this is where grey squirrels shift from “annoying” to “serious”.
Grey squirrel damage to buildings: lofts, wiring, and recurring entry
Grey squirrels commonly target rooflines and loft spaces because they’re warm, quiet and safe. Once inside, the usual problems are:
- Noise and disruption: scratching, running, gnawing — especially early morning and dusk
- Insulation damage: pulled apart for nesting; cold spots and energy loss
- Stored item damage: chewed boxes, bags and stored materials
- Wiring risk: rodents and squirrels gnaw for tooth wear; damaged cables can create a fire risk
- Repeat entry: if you don’t proof the entry point properly, the same route gets used again and again
The key takeaway: if you only “remove the squirrel” but don’t fix access and attractants, you’re setting yourself up for a repeat problem.
Do grey squirrels carry disease?
The headline disease link people search for is squirrelpox. Grey squirrels can carry squirrelpox virus without being badly affected, but it can be rapidly lethal for red squirrels and is a major driver of decline where the virus is present.
For most households, the practical “health” angle is more about hygiene and contamination if squirrels are nesting in lofts or outbuildings — droppings, urine and nesting material are not something you want building up in enclosed spaces. If you’re cleaning contaminated areas, treat it as a risk job: PPE, safe disposal, and don’t spread dust through the property.
Grey squirrels and red squirrel decline: what’s the connection?
There are two main drivers:
- Competition: grey squirrels outcompete reds for food and space in many habitats
- Disease: squirrelpox carried by greys can devastate local red populations and speeds up decline dramatically where it’s present
If you’re in or near red squirrel areas, this becomes a conservation issue as well as a property/land management one.
Grey squirrel legal UK: the bit people get wrong
The biggest confusion is “relocating” squirrels. In the UK, grey squirrels are treated as an invasive non-native species, and guidance is clear that relocating and releasing them is not a casual option. If you trap one, you should not assume you can simply drive it elsewhere and let it go.
If you’re not sure what’s lawful in your situation — especially if you’re on a boundary between nations, dealing with protected wildlife nearby, or thinking about lethal control — don’t guess. This is exactly where a competent professional saves you risk.
What to do if you have grey squirrels in a loft or outbuilding
Start with prevention and proofing logic. The goal is to remove easy routes and easy food, so squirrels stop targeting your site.
- Identify entry routes: roofline gaps, broken soffits, lifted flashing, uncapped vents, damaged mesh, open eaves
- Cut access from trees: trim back branches that overhang roofs and outbuildings (where practical and safe)
- Remove attractants: unsecured bird feed, open waste, accessible animal feed
- Don’t create new entry points: rushed DIY repairs often leave gaps and weak materials that get reopened
- Don’t ignore electrics: if you suspect wiring has been gnawed, get it checked
If squirrels are already established, you usually need a structured approach: confirm routes, remove pressure legally and safely, then seal properly so it doesn’t repeat.
When it’s time to call a pest controller
DIY becomes false economy when you’re dealing with repeat entry or high risk. It’s usually worth calling a pest controller when:
- you suspect wiring damage
- you’re unclear on what’s lawful in your situation
- you’re managing woodland/estate damage rather than a one-off nuisance
Professionals don’t just “remove squirrels”. The value is in getting a safe plan and the proofing right so the site stops being attractive.
Frequently Asked Questions
Are grey squirrels pests in the UK?
They can be. Grey squirrels cause significant tree damage (especially bark stripping), can enter buildings and lofts, and are linked to red squirrel decline through competition and squirrelpox.
Do grey squirrels damage trees?
Yes. Bark stripping can weaken or kill trees, reduce timber value and create long-term woodland management costs. Official guidance estimates bark stripping costs at least £37m per year in England and Wales.
Can grey squirrels cause house fires by chewing wires?
Gnawing on cables is a known risk with rodents and squirrels. If you suspect wiring damage in a loft or outbuilding, get it checked by a competent electrician rather than ignoring it.
Is it illegal to relocate grey squirrels in the UK?
Relocating and releasing grey squirrels is not a casual option in the UK because they’re treated as an invasive non-native species. If you trap one, don’t assume you can transport it elsewhere and release it.
What should I do if I find a grey squirrel in my loft?
Don’t rush into unsafe access. Confirm entry points at the roofline, reduce attractants, and plan proper proofing. If squirrels are established or access is at height, professional help is usually the safest route.
Do grey squirrels carry disease?
Grey squirrels are linked to squirrelpox virus, which can be fatal to red squirrels. For most homes, the practical risk is hygiene and contamination if squirrels are nesting in enclosed spaces.
Why do grey squirrels affect red squirrels?
They outcompete reds for food and habitat and can carry squirrelpox virus, which can devastate local red populations where it’s present.
How do I stop grey squirrels getting into my roof?
Reduce access: repair soffits and roofline gaps, cap or mesh suitable vents correctly, and cut back overhanging branches where practical. Proofing needs to be robust, or the same route gets reopened.
Additional resources
Official and reputable sources for UK law, tree damage and conservation context:
- GOV.UK: Grey squirrel damage to trees (visual guide)
- GOV.UK: Non-native species release licensing guidance
- Legislation.gov.uk: Invasive Alien Species (Enforcement and Permitting) Order 2019
- APHA: Red squirrels and squirrelpox (science blog)
- RSPCA: Keeping squirrels out of gardens (and legal note on relocation)
- Forest Research: Management of grey squirrels (woodland context)