Knives, offensive weapons and serious violence

When is it illegal to possess a knife?

It is a criminal offence to possess any knife or other bladed article in a public place, under section 139 of the Criminal Justice Act 1988. It is also a criminal offence to have an “offensive weapon” in any public place, under section 1 of the Prevention of Crime Act 1953.

Both offences carry maximum penalties of up to four years’ imprisonment. It is a defence for someone to prove they have possessed a knife, bladed article or offensive weapon with “good reason or lawful authority”, though the legislation does not provide examples of what this means in practice. A court determines whether the explanation provided by a defendant amounts to lawful authority or reasonable excuse based on the specific circumstances of a case.

It is also a criminal offence to possess in private any prohibited weapon under section 141 of the Criminal Justice Act 1988 (as amended by the Offensive Weapons Act 2019). Prohibited weapons are also illegal to sell, hire, lend or manufacture. The maximum penalty is 51 weeks’ imprisonment.

Prohibited weapons are listed in secondary legislation under the Criminal Justice Act 1988 (Offensive Weapons) Order 1988, and include a range of knives, bladed articles and other weapons. Under section 141(2) of the 1988 act, the government can introduce secondary legislation to add further weapons to this list. In 2024, the government added a new definition of “zombie-style” knives and machetes to the list. In 2025, it added “ninja swords” to the list.

Sentencing statistics from the Ministry of Justice shows that in the year ending March 2023, there were almost 18,500 cautions and convictions made for possession of a knife or offensive weapon. Juveniles (aged 10-17) were the offenders in around 17.3% of cases.

Further data for England and Wales related to knife-related offences can be found in the Library briefing: Knife Crime Statistics: England and Wales.

What are the restrictions on the sale of knives in the UK?

Knives and bladed articles can be legally bought and sold by anyone over 18 years of age, in physical premises and online. Any retailer that sells such an item to someone under the age of 18 may commit an offence under section 141A of the Criminal Justice Act 1988. This is enforced by both the local Trading Standards team and the police.

Part 3 of the Offensive Weapons Act 2019 creates additional requirements for online retailers and delivery companies to demonstrate they have taken “all reasonable precautions and exercised all due diligence” to avoid selling or delivering knives to people under the age of 18.

Retailers must not market knives in a way that encourages their use for violence, as set out under the Knives Act 1997. In addition, online platforms and social media companies have a duty under the Online Safety Act 2023 to prevent the sale of offensive weapons and knives to people under 18.

What enforcement powers do authorities have?

Police officers have specific powers to stop and search people whom they have reasonable grounds to suspect possess a knife or bladed article, under section 1 of the Police and Criminal Evidence Act 1984.

In certain circumstances, the police can also search without reasonable grounds, when authorised by a senior officer under section 60 of the Criminal Justice and Public Order Act 1994, or when stopping an individual who is subject to a Serious Violence Reduction Order.

Stop and search is considered by many experts as an imprecise tactic, with a disproportionate impact on Black men and boys. The Library briefing Police powers: stop and search provides further information on stop and search powers.

Knife crime offences carry potentially heavy penalties, including lengthy prison sentences. Guidance published by the National Police Chiefs’ Council, College of Policing and the Crown Prosecution Service (PDF) recommends that knife crime offences should be prosecuted in all cases, except where the perpetrator is a child and it is their first offence, in which case a caution or alternative disposal can be applied.

A second conviction for a knife possession offence, or a first conviction for the offence of threatening with a bladed article, can result in a mandatory minimum custodial sentence, as detailed under the Sentencing Act 2020.

How is the government working to tackle knife crime and prevent serious violence?

The government has proposed several measures through its Crime and Policing Bill 2024-25 aimed at restricting the use and supply of knives and offensive weapons. The bill would:

• create a new offence of possessing a knife or offensive weapon with intent to use it to cause harm
• increase the maximum penalty for manufacturing, selling, hiring, or lending prohibited weapons
• give the police greater powers to seize knives from properties
• allow the police to require online businesses to remove illegal content related to knives and offensive weapons and to issue fines to both businesses and senior executives who fail to comply
• establish additional requirements for online sellers, delivery companies and delivery drivers to ensure that knives are not sold or delivered to a person aged under 18
• require retailers to report to the police when someone buys knives in bulk

These provisions are detailed in section 3.2 of the Library briefing Crime and Policing Bill 2024-25: Progress of the bill. At the time of writing, the bill is awaiting second reading in the Lords.

In addition to these legislative commitments, the government has launched the Coalition to Tackle Knife Crime. The government says the coalition will bring together the police, health services, education service, charities, young people, victims’ families, technology companies, and sports organisations “to develop an extensive understanding of what causes young people to be dragged into violence”.

The government has also committed to establishing local ‘Young Futures’ prevention partnerships to bring together services to support at-risk teenagers.