UK Knife Law: What Knives Are Legal in the UK

Three inches, 7.62cm, non-locking. That single measurement decides whether a folding knife can be carried in a UK public place without a reason.

Section 139 of the Criminal Justice Act 1988 makes it an offence to have a bladed or sharply pointed article with you in public. The one exception is a folding pocketknife with a cutting edge of 3 inches or less ^[1]. The exemption only applies if the knife also does not lock open. A locking folder, a fixed blade, or any blade over 3 inches needs a good reason or lawful authority. Some knives are banned regardless of length or reason.

This rule causes the most confusion because retailers use “UK legal” as a marketing term rather than a legal test tied to a specific statute. This hub states the statute first. Then it gives the practical rule. The England and Wales, Scotland and Northern Ireland differences are set out separately below.

Start with the cutting-edge and locking test, then compare the four carry-status categories and the rules for public places, sales and travel. The sections below also explain banned knives, multitools and differences across the UK.

What is the legal blade length for a pocket knife in the UK?

A folding knife with a cutting edge of 3 inches (7.62cm) or less can be carried in public without a reason. That only applies if it also does not lock open. The measurement runs along the cutting edge itself. It excludes the handle and the rest of the knife’s length.

Section 139(2) and (3) of the Criminal Justice Act 1988 set the exemption. The offence covers any bladed or sharply pointed article “except a folding pocketknife”. It covers a folding pocketknife only “if the cutting edge of its blade exceeds 3 inches” ^[1]. Scotland’s section 49(3) puts the same rule the other way round. It exempts a folding pocketknife whose cutting edge “does not exceed three inches (7.62 centimetres)” ^[3]. A slipjoint knife, a keyring knife, or a small non-locking multitool blade under that length meets the test. A locking folder does not meet the test, whatever its blade length. That is because it is not a folding pocketknife for the purposes of this exemption. ^[1]

Anything longer than 3 inches needs a good reason to carry in public. So does any locking or fixed blade of any length. The next sections set out what counts.

What are the four UK knife carry statuses?

Every knife sold or carried in the UK falls into one of four carry statuses: legal to carry, good reason needed, illegal to carry in public, or banned outright. The table below gives the rule and a typical example for each.

The status depends on the knife and the situation together. It is not about the knife alone. A locking folder is not banned. It is legal to own. It becomes an offence only when carried in public without a reason the law accepts. ^[2]

Can you carry a pocket knife in the UK?

Yes, if it is non-locking and its cutting edge is 3 inches or less. Carrying any bladed or sharply pointed article in public requires good reason or lawful authority outside that exemption.

The defence sits with the person carrying the knife. It does not sit with the police. Section 139(4) states it is a defence to prove good reason or lawful authority. This means the burden of proof falls on the person stopped. It does not fall on the prosecution to disprove it. ^[1]

Are lock knives illegal in the UK?

No. Lock knives are legal to own. They do not qualify for the automatic 3 inch carry exemption though. Courts have established that a knife which locks in the open position is not a folding pocketknife for section 139 purposes. This includes a button, lever, or ring lock. It applies regardless of blade length.

In practice, a knife with a cutting edge of 3 inches (7.62 cm) or less and a lock still needs a good reason to carry. A friction folder of the same length with no locking mechanism does not.

What counts as good reason to carry a knife?

The statute names three examples of good reason: use at work, religious reasons, and national costume. Section 139(5) lists them. Section 139(4) leaves room for any other good reason the person can prove ^[1]. General self-defence does not qualify.

The Crown Prosecution Service states that carrying a weapon because of a constant or enduring threat does not amount to self-defence or a reasonable excuse, even for a genuine threat. It records only a narrow exception for an imminent and specific attack (Evans v Hughes) ^[11]. Forgetfulness alone is not a reasonable excuse either ^[11].

What knives are banned outright in the UK?

Flick knives, gravity knives, butterfly knives, disguised knives, and zombie-style knives and machetes are all banned regardless of blade length or reason for carrying. The zombie-style knife and machete ban has applied in England and Wales since 24 September 2024. Banned means it is an offence to manufacture, sell, hire, import, or in most cases possess these items at all.

A zombie-style knife or machete is defined in law as a bladed article with a plain cutting edge and a sharp pointed end. The blade must also be over 8 inches. It must also have a serrated edge, more than one hole in the blade, spikes, or more than two sharp points ^[9]. That order extends to England and Wales only ^[9]. Antiques over 100 years old are exempt from the banned list. Flick knives and gravity knives are the exception. They get no antique exemption ^[2].

The full list, the surrender scheme, and the changes made but not yet in force are on Banned Knives in the UK: The Full List.

What are the rules for buying knives online in the UK?

A seller must deliver a bladed product into the hands of an adult at residential premises. A seller must not arrange delivery to an unattended locker for collection. This sits alongside the standard rule that it is illegal to sell most knives to anyone under 18.

Section 38 of the Offensive Weapons Act 2019 makes it an offence for a remote seller to deliver a bladed product, or arrange its delivery, to a locker ^[12]. A locker means a lockable container for buyer collection. Section 38 has been in force in England and Wales since 6 April 2022 and in Scotland since 28 June 2022. Legislation.gov.uk records no Northern Ireland commencement ^[12]. Full detail on age checks and delivery rules is on Buying Knives Online in the UK: Age and ID Rules.

Can you take a knife when travelling in the UK?

No knife should go in hand luggage on a UK flight. gov.uk’s hand luggage rules bar any tool with a blade or shaft longer than 6cm. Security staff can also refuse smaller blades. Pack a knife in hold luggage instead. Wrap it securely and check the airline’s own rules, which can be stricter.

Full detail on flights, Eurostar, ferries, and the sgian-dubh at airport security is on Knives When Travelling: Flights, Ferries and Trains.

Are multitools and Swiss Army knives legal in the UK?

A non-locking multitool blade of 3 inches (7.62 cm) or less is legal to carry without a reason. A locking multitool blade is not legal to carry without a reason, whatever its length. The same rule that governs single-blade folding knives applies directly to multitool blades.

Full detail on Leatherman, Victorinox and other multitool brands is on Multitools and Swiss Army Knives: UK Carry Rules.

Is UK knife law different in Scotland and Northern Ireland?

Yes. The statute used, the wording of the defence, the penalties, and one sale-age detail all differ. All three jurisdictions share the same 3 inch folding-pocketknife exemption.

Section 172 of the Criminal Justice Act 1988 extends section 139 to Northern Ireland ^[4]. The Northern Ireland version of section 139 carries the same folding-pocketknife exemption. Its maximum is 12 months on summary conviction and 4 years on indictment ^[1]. Northern Ireland also has a separate, general offensive weapon offence at article 22 of the Public Order (Northern Ireland) Order 1987 ^[5]. Section 139 is the bladed-article offence though. Article 54(1) of the Criminal Justice (Northern Ireland) Order 1996 generally prohibits selling a knife or knife blade to a person under 18. The article heading still says “under 16”. The text was changed to 18 ^[6]. Article 2 of the 1997 Exemption Order exempts a folding pocketknife whose cutting edge does not exceed 7.62 cm (3 inches) and razor blades permanently enclosed in a cartridge or housing with less than 2 mm of blade exposed beyond the specified plane from article 54(1) ^[7].

Scotland’s section 49 uses “reasonable excuse or lawful authority” in place of “good reason”. Its maximum is 12 months summary and 5 years on indictment ^[3]. For sales, section 141A as it applies in Scotland keeps the general age at 18. It allows a sale to a person aged 16 or over where the knife or blade “is designed for domestic use” ^[13]. This carve-out was inserted by the 2006 Scottish Act ^[8]. The 1996 Exemption Order also removes qualifying short folding pocketknives and enclosed razor cartridges from section 141A(1) ^[14]. Retailers commonly apply an 18+ policy to all knives.

What is the penalty for carrying an illegal knife in the UK?

Up to 4 years in prison, a fine, or both, on conviction on indictment in England, Wales and Northern Ireland. In Scotland the maximum is up to 5 years. On summary conviction the maximum is 12 months in all three.

In England and Wales the printed text of section 139(6)(a) still says six months ^[1]. Section 282 of the Criminal Justice Act 2003 reads it as the general magistrates’ limit for either-way offences instead ^[15]. Section 224(1A) of the Sentencing Act 2020 has set that limit at 12 months since 18 November 2024 ^[16].

In England and Wales the Sentencing Council’s guideline for bladed articles and offensive weapons sets a starting point of 1 year 6 months’ custody for the most serious cases. Examples include offences at a school or cases with serious alarm or distress. This range rises to 1 to 2 years 6 months’ custody ^[10]. The least serious cases start at a low-level community order where the excuse for possession falls just short of being accepted ^[10].

Why do retailers call a knife “UK legal”?

It is marketing language, not a legal category defined anywhere in statute. No UK law uses the phrase “UK legal knife.” The phrase is retailer shorthand for a folding knife that appears to meet the blade-length and locking test. It is not always applied correctly.

The gap this creates is real. A catalogue page can describe a knife as “UK legal” based on blade length alone. It can fail to mention whether it locks. That detail actually decides the carrying status. Checking blade length and lock type separately against the rule set out above is a better test than trusting a retailer’s label on its own.

How do you check if a knife you already own is legal to carry?

Measure the cutting edge, check whether it locks open, and match both against the table above. This takes under a minute with a ruler. It does not require any tool beyond opening the blade fully.

Measure the cutting edge only. Do not include any unsharpened section near the handle. Do not measure the closed length of the knife. Then open and close the blade by hand. A knife that swings freely at any point without needing a button, lever, or catch released first is non-locking. A cutting edge at or under 3 inches (7.62cm) combined with no locking mechanism meets the automatic exemption. Either condition failing moves the knife into the good-reason category covered on Good Reason to Carry a Knife: What UK Courts Accept.

Where to check UK legal folding knives by product

Every rule above tells you what the law requires. It does not tell you which specific knives on sale today actually meet the test.

UK Legal Pocket Knives: 3 Inches or Less applies the carrying statuses above to named products. The blade length and lock type are checked against manufacturer or named major-retailer specifications.

This is legal information. It is not legal advice. Get advice from a solicitor or Citizens Advice for a specific situation.