Can You Carry a Knife in the UK? Rules, Exceptions, and Penalties

In most situations, you cannot carry a knife in the UK in public. The default position under Section 139 of the Criminal Justice Act 1988 is that having any bladed or sharply pointed article in a public place is a criminal offence. There are only two ways out: the knife is a folding pocketknife with a non-locking blade of three inches or less, or you have a specific good reason for carrying it that day, such as your work, your religion, or national costume. “I keep it for self-defence” is not a good reason, and neither is forgetting it was in your bag.

The Default Rule

Section 139 of the Criminal Justice Act 1988 makes it an offence to have any article with a blade or sharp point in a public place without good reason or lawful authority.¹ The wording is broad on purpose. Kitchen knives, craft blades, multi-tools, letter openers, box cutters — if it has a blade or a point, it falls inside the section.

“Public place” is equally wide. It covers anywhere the public has access, paid or free: streets, parks, pubs, shops, cinemas, football grounds, and all forms of public transport.¹ The offence is one of possession. Once the prosecution shows you had the item in a public place, it is on you to prove a lawful excuse.

The Folding Pocketknife Exception

There is one narrow category you can carry without giving any reason at all: a folding pocketknife. To qualify, the cutting edge must not exceed three inches (7.62 cm), and the blade must fold freely.¹ Both conditions have to be met.

The folding requirement catches a lot of people out. In Harris v DPP, confirmed later in R v Deegan, the courts held that “folding” means the blade must be foldable at any time by the simple folding process, with no button to press or catch to release first. A knife that locks open when deployed is not a folding pocketknife, no matter how short its blade. Lock-blade knives sit under the general rule and need a good reason like any other.

What Counts as a Good Reason

If your knife falls outside the folding pocketknife exception, you can still carry it lawfully, but only with a genuine reason tied to what you’re actually doing at the time. Section 139 lists three examples, and courts recognise others in the same spirit:¹

Use at work. A chef taking knives to a restaurant, a carpet fitter with a Stanley knife, or an electrician with a cable-stripping tool.
Religious reasons. A Sikh carrying a Kirpan as an article of faith is the standard example.
National costume. A Sgian-dubh worn with Highland dress.
Other genuine, specific reasons. An angler taking a fishing knife to a river; someone carrying newly bought kitchen knives home from the shop.

The reason has to fit the moment. Carrying a chef’s knife on a Tuesday commute to the kitchen you work in is fine. Carrying the same knife on a Saturday night out is not. Two answers in particular will make things worse rather than better: “I carry it for self-defence” is expressly not a good reason, and “I forgot it was in there” is not a defence the courts accept.

Knives You Cannot Carry, Own, or Buy Anywhere

A separate category of weapons is banned outright under Section 141 of the Criminal Justice Act 1988 and the Offensive Weapons Act 2019. For these, there is no good reason defence and no folding-blade exception. Possessing, selling, manufacturing, or importing them is unlawful, and that includes keeping them at home.² The prohibited list includes:

Flick knives (switchblades), including designs where the opening mechanism sits outside the handle.
Butterfly knives (balisongs), with a split handle that rotates to reveal the blade.
Disguised knives concealed inside everyday objects like belt buckles, pens, or combs.
Sword-sticks with a blade concealed in a walking stick.
Stealth knives made from non-metallic materials designed to defeat metal detectors.
Zombie knives and zombie-style machetes. The 2024 definition covers knives with a plain cutting edge, a sharp pointed end, and a blade over eight inches, combined with features such as a serrated edge beyond two inches near the handle, multiple holes in the blade, or spikes.
Curved swords with a blade of 50 centimetres or more, measured in a straight line from the top of the handle to the tip.³

Limited exemptions apply to curved swords made before 1954 or hand-forged by traditional methods, and to genuine antiques over 100 years old or items of historical importance.³ Certain religious exemptions also exist, including for zombie-style knives and machetes.

Penalties

Simple possession of a bladed article under Section 139 carries a maximum of six months’ imprisonment on summary conviction in the magistrates’ court, or up to four years on indictment in the Crown Court, with a fine at either level.¹

A second conviction is treated much more harshly. Under Section 315 of the Sentencing Act 2020, anyone 18 or over convicted of a second offence of possessing a bladed article or offensive weapon faces a mandatory minimum of at least six months in prison. For 16- and 17-year-olds, the mandatory minimum is a four-month detention and training order. Courts can go below the minimum only in exceptional circumstances.⁴

Using a knife to threaten someone in public is a separate offence under Section 139AA of the Criminal Justice Act 1988, carrying up to four years’ imprisonment on indictment.⁵ If a knife is used to injure someone, the charges move up to assault, wounding, or worse. A conviction of any kind stays on your record and affects work, travel, and professional licensing for years.

Buying a Knife

You must be 18 or older to buy any knife or bladed article. The one exception is a non-locking folding pocketknife with a blade of three inches or less, which mirrors the carry exception.⁶ In-store, retailers have to check proof of age, though no specific document list is prescribed.

Online purchases are tighter. A tick-box confirming you’re over 18 does not meet the legal requirement for age verification; the seller needs a system genuinely likely to prevent under-18 sales. Delivering a bladed product to a residential address without ensuring it is handed to someone aged 18 or over is an offence, the package has to be clearly marked as containing a bladed article, and the delivery company itself commits a separate offence if it hands the parcel to a minor.⁷

Scotland and Northern Ireland

The rules above sit inside the Criminal Justice Act 1988, which applies in England, Wales, and Northern Ireland. Northern Ireland’s version of Section 139 has identical defences and the same three-inch folding pocketknife threshold.⁸

Scotland has its own statute, Section 49 of the Criminal Law (Consolidation) (Scotland) Act 1995, but the practical effect is the same: carrying a bladed or sharply pointed article in a public place without reasonable excuse is a criminal offence, the same non-locking three-inch folding pocketknife exception applies, and defences for work, religion, and national costume are recognised.⁹

1
legislation.gov.uk. Criminal Justice Act 1988 – Section 139
2
GOV.UK. Statutory Guidance: Offensive Weapons Act 2019 (Accessible)
3
Parliament. Prohibiting Ninja Swords – Legal Description and Defences
4
The Crown Prosecution Service. Knife and Other Weapons Offences
5
legislation.gov.uk. Criminal Justice Act 1988 – Section 139AA
6
GOV.UK. Age Verification for the Sale and Delivery of Knives – Crime and Policing Bill Snapshot
7
GOV.UK. Offensive Weapons Act 2019 Statutory Guidance
8
legislation.gov.uk. Criminal Justice Act 1988 – Articles With Blades or Points and Offensive Weapons
9
legislation.gov.uk. Criminal Law (Consolidation) (Scotland) Act 1995 – Section 49