UK Knife Law for Field Mycologists
A small knife is one of the most useful things in a field mycologist’s kit. It’s also, in the wrong circumstances, a criminal offence to carry. Here’s what UK law actually says, what’s changed recently, and how to make sure your foray kit stays on the right side of it.
Please note
This post is general information, not legal advice. It reflects the law as we understand it in September 2026. The rules differ between England and Wales, Scotland and Northern Ireland, and courts decide every case on its own facts. If you’re unsure, check the official sources listed at the end or speak to a solicitor.
Why do mycologists carry knives at all? To ease a fungus out of rotten wood, to cut through a tough stem, to slice a specimen in half and check the flesh for colour changes, or to trim a sample for the microscope. It’s a working tool, and for most of us it lives in the kit bag alongside a hand lens and field guide.
But the law doesn’t really care whether you’re a mycologist, a gardener or a chef. What it cares about is what kind of knife you’re carrying, where you’re carrying it and why.
The Basic Rule
Across the UK, it’s an offence to have an article with a blade or point with you in a public place without good reason or lawful authority. In England, Wales and Northern Ireland, the offence is in section 139 of the Criminal Justice Act 1988. In Scotland, it’s section 49 of the Criminal Law (Consolidation) (Scotland) Act 1995, where the defence is called a “reasonable excuse”.
“Public place” is a wide term. It includes streets, car parks and public transport, but also public footpaths, country parks, nature reserves and any woodland the public can get into. In other words, most of the places we go looking for fungi.
“With you” is wide too. A knife in your rucksack, your basket or your car is still with you in the eyes of the law.
The Pocketknife Exception
There’s one important exception. You can carry a folding pocketknife without needing any reason at all, as long as the cutting edge of its blade is 3 inches (7.62 cm) or less. That exception applies in England and Wales, Scotland and Northern Ireland.
What counts as a folding pocketknife?
The blade must fold into the handle, the cutting edge must be no longer than 3 inches (7.62 cm), and it must not lock. If you have to press a button, release a catch, slide a lever or twist a ring before the blade will fold, it’s a lock knife, and the law treats lock knives the same as fixed blades, however short they are.
That last point catches out a lot of people. In Harris v DPP (1993), the High Court decided that a lock knife isn’t a “folding pocketknife”, and that ruling has stood ever since. So in England and Wales a small lock knife with a 2-inch blade needs a good reason to be carried in public, just as a large fixed-blade knife would. Scotland’s law has the same 3-inch pocketknife exception, and the safest assumption is that lock knives aren’t covered there either.
What about mushroom knives?
Plenty of knives sold for mushroom hunting fall within the exception, but many don’t. Before your next foray, check yours:
- Does it lock? Many popular folding knives have a locking ring, a liner lock or a back lock. If it locks, it isn’t covered by the exception.
- How long is the cutting edge? Measure the sharpened edge, not the whole blade. If it’s over 3 inches (7.62 cm), it isn’t covered.
- Is it a fixed blade? Fixed-blade knives always need a good reason to be carried in public, whatever their size.
A knife is a handy part of any foray kit. Just make sure it’s one you can legally carry — unlike the one in this photo
What Counts as a Good Reason?
If your knife doesn’t fit the pocketknife exception, you’ll need a good reason (or, in Scotland, a reasonable excuse) to have it with you in public. The law specifically recognises carrying a knife:
- for use at work
- for religious reasons, such as the kirpan some Sikhs carry
- as part of national costume
Beyond those, it’s for a court to decide whether your reason was good enough, and it depends on the circumstances. A professional ecologist with a lock knife in their survey kit may well have a good reason. Someone who’s still carrying the same knife around town a week after their last foray probably doesn’t. Carrying a knife “for self-defence” is very unlikely to be accepted.
So could recording fungi be a good reason? Possibly, if you’re genuinely on your way to a foray, at one or heading home, and the knife is clearly part of your kit. But “possibly” is doing a lot of work in that sentence. There’s no guarantee a court would agree, and before it ever got that far you might have to explain yourself to a police officer. The simplest way to avoid the question altogether is to carry a knife that falls within the exception.
Banned Knives
Some knives are banned outright, which means it’s illegal to buy, sell or even own them at home. In England and Wales, the banned list includes:
- flick knives and gravity knives
- butterfly knives
- disguised knives, such as blades hidden in belt buckles, phones or lipsticks
- push daggers
- zombie knives, and since 24 September 2024, zombie-style knives and machetes
- ninja swords, since 1 August 2025
Scotland and Northern Ireland have their own, similar lists. It’s very unlikely anything in a mycologist’s kit falls into these categories, but it’s worth knowing that the list keeps growing.
The Penalties
This isn’t something to take lightly. The maximum penalties for carrying a knife in public without good reason are serious in every part of the UK.
Maximum penalties for carrying a knife illegally in public
| Where | Law | Maximum sentence |
|---|---|---|
| England and Wales | Criminal Justice Act 1988, section 139 | 4 years in prison, an unlimited fine, or both |
| Scotland | Criminal Law (Consolidation) (Scotland) Act 1995, section 49 | 5 years in prison, a fine, or both |
| Northern Ireland | Criminal Justice Act 1988, section 139 | 4 years in prison, a fine, or both |
In England and Wales, an adult convicted of a second knife possession offence faces a minimum of six months in prison, unless the court decides that would be unjust in the circumstances.
What’s New: the Crime and Policing Act 2026
The Crime and Policing Act 2026 became law in April 2026, and its measures are being brought into force in stages. They apply mainly in England and Wales. For most mycologists nothing changes day to day, but it’s worth knowing what’s coming:
- A new offence of having a knife or offensive weapon with intent to use unlawful violence, with a maximum of 7 years in prison.
- Tougher maximum penalties, up to 2 years in prison, for selling knives to under-18s and for selling or possessing banned weapons.
- Stricter age checks when you buy a knife online. Sellers must check photo ID, and couriers must check ID on delivery rather than leaving parcels on the doorstep or with a neighbour.
- New police powers to seize knives, including from private property, where there are reasonable grounds to suspect they’ll be used in unlawful violence.
The practical upshot for us is simple. Once these rules are in force, if you’re buying a new foray knife online, expect to show photo ID when you order and again when it’s delivered.
Practical Advice for Field Mycologists
Keeping your foray kit legal
- Choose a non-locking folding knife with a cutting edge of 3 inches (7.62 cm) or less. It’s all most of us need, and you can carry it without needing a reason.
- If you do use a lock knife or a fixed blade, only take it when you’re actually going on a foray, keep it packed away in your kit rather than on your belt, and unpack it as soon as you get home.
- Don’t leave knives in your car, coat pocket or rucksack between trips.
- Leave knives at home if a foray involves a school. Carrying a knife on school premises is a separate offence with its own rules, and many other venues won’t allow knives either.
- If a police officer asks about your knife, stay calm, be honest and explain exactly what it’s for.
- Ask yourself whether you need a knife at all. A small trowel or an old teaspoon is often better for easing a fungus out of the ground with its stem base intact.
A quick word on picking fungi
Knife law is only one part of foraying legally. Picking fungi has its own rules too. You should have the landowner’s permission, many nature reserves and parks have byelaws that ban picking altogether, and a handful of species are protected by law. Our introduction to UK protected fungi species explains more.
The Bottom Line
Nobody wants a great day in the woods to end with an awkward conversation with the police. The good news is that staying legal is easy. Pick the right knife, carry it only when you need it and keep it packed away. Then you can get on with the important part: finding, photographing and recording fungi well.
Official sources
Published by
L. Terry