Weapons and the law

Are you tempted to carry a weapon? Make sure you know all about UK knife laws, weapon laws and gun laws before you end up doing several years in prison or getting an unlimited fine.

A young person is standing in the street. They are wearing a blue hat and have long blonde hair. They are thinking about weapons and the law

What is an offensive weapon?

Legally speaking, an offensive weapon is any object that has been made or adapted to cause injury.

This covers:

  • Weapons built for the sole purpose of hurting people, like a knife or gun.
  • Something adapted to cause injury, like a sharpened snooker cue.
  • An object not designed to hurt anyone, but you’re carrying it around intending to cause injury, like nail scissors.

In defining what counts as a weapon, your intention (whether you meant to hurt someone) could be taken into account – depending on what you’re carrying.

If you’re caught with an offensive weapon

In the eyes of the law, it doesn’t matter if you were carrying a weapon around with you but weren’t planning to hurt anyone. If it’s obviously a weapon, you’re in trouble. And claiming you’re carrying it round for someone else isn’t an excuse either.

The only defence in law is “lawful authority or reasonable excuse”. It’s down to you to show that the weapon in question wasn’t made or adapted to cause injury.

If you’re arrested and found guilty of carrying an offensive weapon in public, you could get up to four years in prison.

And if, for any reason, you hurt someone (grievous bodily harm), kill or almost kill someone, you could face life imprisonment.

Learn more about your rights on arrest here.

Knives and the law in the UK

It’s illegal to carry a knife in public, even if you’re not behaving in a threatening manner and don’t plan to use it. Carrying a knife in the UK could see you facing a penalty of four years’ imprisonment and a £5,000 fine for doing so.

It isn’t illegal in the UK to own a knife in private, like the bread knife in your kitchen. However, if any knife is used in a threatening way, in a private environment, like your house, it becomes an offensive weapon.

Legal exceptions for carrying a knife

Under certain circumstances, it’s legal to be in possession of a knife in public. Good reasons to carry include:

  • If it’s a tool of the trade (i.e. you work in catering or carpentry).
  • For religious reasons (i.e. a Sikh kirpan).
  • If it’s a penknife (pocket or folding knife) less than three inches long (although it may be considered offensive if carried for the purpose of causing injury or harm).

Are butterfly knives illegal in the UK?

Yes, butterfly knives are illegal in the UK. In fact, this type of folding blade has been a banned knife since 1989.

There are some other knives which you cannot own under any circumstances, including:

  • Flick knives, also known as ‘switchblades’ – where the blade is hidden but shoots out when a button is pressed.
  • Disguised knives – where the blade is hidden inside something like a belt.
  • Sword-sticks.
  • Samurai swords.

Swiss Army knives are allowed under UK knife law, so long as the blade is under 7.62cm. However if any knife is used in a threatening way it becomes an offensive weapon.

Clearly the punishments are severe, so why do people carry knives? We look into that question here. If you are feeling threatened and need support, the first thing to do is tell someone about the problem – whether it’s a teacher at school or another trusted adult. If you don’t think you can speak to anyone you know, get in touch with The Mix’s helpline, or contact Childline.

Is it legal to own a sword in the UK?

It is now illegal to sell any type of sword that has a curved blade longer than 50 cm unless it was either hand forged in a traditional way, an antique (at least 100 years old), or if it’s a samurai sword made before 1954.

When it comes to other types of swords, UK law does not require you to have a licence to purchase or have one in your home, but don’t go walking about with it in public unless you have a valid reason, such as travelling from some kind of martial arts or war reenactment event. Even if you have a good excuse, the sword should be concealed, because – technically speaking – you’re not actually a medieval knight.

Handing in a weapon

Police authorities regularly hold weapons amnesties where you’re free to hand in an offensive weapon without risk of prosecution.

Outside an amnesty, your circumstances dictate how the police would receive you. Whatever the reason you’re in possession of an offensive weapon, police advice is to contact your local station to make arrangements for handing it in.

If you’ve simply found a gun or a flick knife in public, police advice is not to touch it, but report the find by phone or in person at the local station.

Which other weapons are illegal?

When it comes to purchasing firearms, individuals often encounter various legal restrictions and regulations to ensure responsible ownership. The process involves obtaining a license, with stringent criteria in place to evaluate an individual’s suitability. This includes demonstrating a legitimate purpose for owning a gun and airgun, such as vermin control or possessing an antique firearm.

In the digital age, the landscape of firearm purchasing has expanded to include online platforms. Websites such as 460rowland.com/ offer a convenient avenue for enthusiasts to explore and acquire firearms. However, even in the online realm, adherence to legal requirements and responsible ownership remains crucial. Prospective buyers must navigate through the digital space with the same diligence and respect for regulations as they would in a physical store, ensuring that the acquisition of firearms is conducted within the bounds of the law and safety guidelines.


You need to have a licence to own a gun and there are strict restrictions on getting one, such as proving you’ll only be using it to kill vermin, or that it’s an antique-type gun. You also have to get two people to tell the police that you’re responsible enough to own a gun.


These come under different laws from guns that use bullets. People under 18 aren’t allowed to buy guns or ammunition. If you are under 18 you can use an airgun at a registered gun club or if someone over the age of 21 is responsible for you.

Learn more about crime and safety in the rest of our articles here.

Next Steps


law| weapons

By The Mix Staff

Updated on 16-Dec-2022