There are a number of different types of weapon offences under English law. The primary weapon offences can be summarised as:

  1. Possession of offensive weapon/s
  2. Possession of a knife/bladed article
  3. Possession of a firearm (both real and imitation)

Possessing an offensive weapon in a public place is an offence contrary to section 1 of the Prevention of Crime Act 1953.

What is classified as an offensive weapon in UK law?

The law recognises three categories of offensive weapon:

  1. Those where objects are made for use for causing injury to the person. These items are legally classified as ‘offensive weapons per se’ and include flick knives, kitchen knives, butterfly knives, pepper sprays, knuckle dusters and nunchucks
  2. Those where objects are adapted for such a purpose, i.e. to cause injury to a person. This includes items that would otherwise be incapable of causing injury but have been changed so that they now can, for example a sock containing a snooker ball, a sharpened stick or a sharpened snooker cue, or a water pistol filled with acid
  3. Those where objects are not so made or adapted but carried with the intention of causing injury to the person, for example a cup of bleach carried with the intent of throwing it into someone’s face to cause injury, sharpened nail scissors or a baseball bat

In the first two categories of offensive weapon, the prosecution does not have to prove that the accused had the weapon with him/her for the purpose of inflicting injury. If the court is certain that the weapon is offensive, an individual will only be acquitted if he or she establishes the defences of lawful authority or reasonable excuse.

Under the third category, the prosecution must prove the accused had the object with him or her with the requisite intention to cause injury.

On occasion, individuals have been accused of possessing an offensive weapon due to the fact that they have had articles which could be offensive weapons in law on their person,  which they have had for perfectly innocent reasons. For example, articles that have been used in connection with work or home DIY such as utility knives or hammers can be mistaken as offensive weapons by overzealous police officers.

When is the possession of an offensive weapon permitted by UK law?


In terms of potential defences in law, the defence of lawful authority is a reference to those people who from time to time carry an offensive weapon as a matter of duty, such as a soldier with a rifle or a police officer with a truncheon. Whilst they are carrying an offensive weapon, they are doing so under lawful authority.

Under certain circumstances, individuals in positions of authority and protection such as security guards or door staff may be permitted to carry offensive weapons, but this will very much depend on the surrounding facts of the alleged offence.

The question of the defence of reasonable excuse is a complex mixture of law and fact and often a lawyer will be required to explain where a certain set of facts will lie.

Examples of reasonable excuse may be:

  1. Finding an offensive weapon and being discovered carrying it on the way to hand it in to the police station
  2. Possession of a weapon having disarmed another
  3. The legitimate transportation of an offensive weapon, such as when moving house or taking it home having purchased it in a shop

Again, it is impossible to give a comprehensive list of what can and cannot constitute a reasonable excuse, as this will vary on a case by case basis.

Where an individual carries a weapon for their own protection and can show on a balance of probabilities that they fear an ‘imminent attack’, this is capable of constituting a reasonable excuse. With the words ‘imminent attack’ not being defined in law, it is for the court to determine how imminent, how soon, how likely and how serious the anticipated attack has to be to allow a reasonable excuse.

Previous cases in the higher courts suggest that – as a matter of law – where an accused has been attacked and fears that the offence might be repeated, carrying a weapon for a day or two after the attack may be regarded as ‘reasonable’, bearing in mind all of the other circumstances.

Forgetfulness that one has or had an offensive weapon on their person alone cannot be a reasonable excuse for carrying an offensive weapon, but the combination of forgetfulness and the circumstances of the article’s acquisition may be.

If one is relying on a defence of lawful authority or reasonable excuse the burden and standard of proof is on the accused and is the balance of probabilities.

What is the sentence for carrying an offensive weapon?


The possession of an offensive weapon is an extremely serious offence which normally carries a term of imprisonment. The maximum sentence which can be handed down in the magistrates’ court is 6 months imprisonment and/or a fine (for a single offence). At the crown court, the maximum sentence is four years imprisonment and/or a fine.

The sentence that a court may be pass very much depends on the circumstances of the offence. The sentence of the court may be seriously aggravated if the offence is committed whilst the defendant is on bail, or if the offence takes place:

  1. On premises such as a school, a hospital or other place where vulnerable people may be present
  2. At a large public gathering, especially one where there may be a risk of disorder
  3. On public transport
  4. On licensed premises or premises where people are carrying out public services, such as in a doctors’ surgery or at a social security office

What is the law on knives in the UK?

Section 139 of the Criminal Justice Act 1988 prohibits the possession in a public place of any article that has a blade or is sharply pointed. Section 139A of this act extends the geographical scope of these offences to school premises. Section 139AA of this act relates to an offence of threatening with an article with a blade, a point or an offensive weapon.

It is therefore illegal to carry any knife in public, even if you’re not behaving in a threatening manner and don’t plan to use it.

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 such as your house, it becomes an offensive weapon.

Are there any legal exceptions for carrying a knife?


Under certain circumstances, it’s legal to be in possession of a knife in public, including:

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

Which knives are illegal in the UK?

There are some knives which you cannot legally own under any circumstances under UK law, including:

  • Flick knives – also known as ‘switchblades’ – where the blade is hidden but shoots out when a button is pressed
  • Butterfly knives – where the blade is hidden inside a handle that splits in two around it
  • Disguised knives – where the blade is hidden inside something like a belt
  • Sword-sticks
  • Samurai swords (unless the item is regarded as decorative, antique or an ornament object)

Swiss Army knives are permitted, providing the blade measures under 7.62cm. However if any knife is used in a threatening way, it becomes an offensive weapon.

What other weapons are illegal in the UK?

As well as knives, other items defined as offensive weapons under UK law include firearms – or guns.

The unlawful possession and use of firearms is generally recognised as a grave and serious offence which is typically tried at the crown court. The punishment for the unlawful possession and use of firearms almost invariably attracts lengthy terms of imprisonment. Under the Firearms Act 1968, there a variety of different types of offences relating to possession and use of firearms.

There are also mandatory minimum terms of imprisonment fixed by law for certain firearms offences under the Firearms Act 1968, such as an offence under the S5 Firearms Act 1968.

The Firearms Act 1968


Under the Firearms Act 1968, a firearm is defined as ‘a lethal barrelled weapon of any description from which any shot, bullet or other missile can be discharged’.

It is an offence to:

  1. Be in possession of a firearm or a dangerous air-weapon and certain ammunition without a certificate
  2. Be in possession of a shotgun without a certificate
  3. Be in possession of a prohibited weapon

Gun licences

You can only legally own a gun if you have a licence and it is not easy to get hold of one. Acquiring a gun licence is a long and complicated process, starting with an application form which asks specific questions about why the individual wishes to own a gun.

There are two types of certificate that can be applied for:

  1. A firearm certificate
  2. A shotgun certificate

The criteria are tougher for firearms than shotguns because shotguns, by definition, can only carry two cartridges. Shotguns that are capable of carrying more rounds must be classed as firearms.

In order to gain a gun licence, two independent referees have to provide confidential character statements in which they are expected to answer in detail about the applicant’s mental state, home life and attitude towards guns. Prospective gun owners must also prove they have good reason to own a gun, a secure place to store it and be willing to have an interview with the relevant police department.

Once the person is approved and given a gun licence, they must renew it every five years.

Note: This guide is intended to give general information only and not intended to be used as the basis upon which advice is given nor should it be relied upon as giving advice specific to a case or individual.

Lawtons do not accept liability for anyone using this guide. Should you require specific advice in connection with a real case or situation, please contact us so we can provide specific legal advice and assistance.