Knife Crime and Gangs: Talking to a Teenager You Care About

Plenty of people in London get as far as thinking seriously about fostering a teenager, then stop at one thought: what if he gets pulled into something with a knife in it? It is a fair worry, and nobody should talk you out of it with a slogan. Here is what the law says, what you would realistically notice, what to do if you find a knife in your house, and what happens if your young person is stopped and searched.

Please note: this is general information about the law in England and Wales, correct at 6 November 2026, and not legal advice. For the current legal position on knives, see the government’s own page on selling, buying and carrying knives.

The worry is reasonable, and the numbers are moving

Two things are true at once, and most coverage only gives you one of them. Nationally, knife crime is falling: police in England and Wales recorded 48,774 offences involving a knife or sharp instrument in the year to March 2026, down 8% on the 53,096 the year before, and homicides involving a sharp instrument fell from 204 to 176 (Office for National Statistics, 23 July 2026). The other truth is local. The House of Commons Library’s knife crime briefing of October 2025 put the Metropolitan Police area at the highest rate of any force in England and Wales, 182 offences per 100,000 people in 2024/25.

London is the sharp end, then. But the figures do not say that a teenager who moves into your spare room is on a path to any of it: the overwhelming majority of young people in care here go to school, argue about the wifi and never go near a weapon.

Most young people who carry are frightened, not dangerous

Ask a young person why they carry and the answer is almost never “because I want to hurt someone”. It is protection. It is the belief that everyone on the bus home already has one. Sometimes it is status, or the price of staying in with a group who have made it a condition. A knife is carried far more often by a frightened child than by a dangerous one. You are not confronting a criminal. You are talking to someone who has decided the world is not safe and has made a bad plan about it. That is why the moral argument bounces off and the practical one lands: carrying does not make a young person safer, it makes them more likely to be hurt in a fight that would otherwise have been a shove. For a young person who has already lived through trauma and unsafe adults, feeling unprotected is not an abstract fear. Take the fear seriously first. Argue about the knife second.

What the law actually says

Get this right before you say it out loud, because a sixteen-year-old will test you and stop listening if you are wrong. The main rules in England and Wales:

• It is against the law to carry most knives in a public place without a good reason. The exception is a folding pocketknife with a cutting edge of 3 inches or less, as long as it does not lock.
• The maximum penalty for an adult carrying a knife or weapon illegally is four years in prison, an unlimited fine, or both.
• Most knives cannot be sold to anyone under 18.
• Some weapons are banned outright, wherever they are kept, including zombie-style knives and machetes, ninja swords, butterfly knives and knuckledusters.
• The Crime and Policing Act 2026 creates a new offence of having a weapon with intent to use unlawful violence, carrying up to seven years. Check the government’s page above for when it applies.

“Good reason” does the heavy lifting in the first rule, and it is narrower than young people assume. Carrying a blade to a fishing trip is a reason. Carrying one because of what happened to a friend in June is not.

What you would actually notice

Taken one at a time, almost every warning sign describes an ordinary teenager, and a carer who treats a new friendship as evidence will lose the relationship that was the real protection. What matters is a cluster, and a change: things that were not like this in August and are now, with secrecy wrapped around them.

• new friends who are noticeably older and never brought home
• being picked up and dropped off in cars by people you have not met
• a second phone, or being unusually guarded about the first one
• trainers or cash that nobody can explain
• a knife missing from the kitchen drawer

The signal worth more than all of those is fear. A young person who has started changing their route home, or who will not walk to the shop after dark, is telling you something whether or not they have words for it yet. Swagger is easy to spot and often means nothing. Frightened is the one to act on. If the pattern points towards older people using a young person, our guide to child exploitation and county lines is the next thing to read. Online life is part of the same picture, and our guide to online safety and a foster child covers what is worth watching.

The conversation, and what to do if you find a knife

Big conversations rarely happen across a kitchen table. They happen sideways: in the car, or drying up after dinner. Say what you have noticed rather than what you have concluded, and let the silences run. Do not promise to keep it to yourself, because you cannot, and a promise you break is worth less than an honest “I will have to tell Sarah, and I will tell you what I am telling her”. Our piece on communicating with a foster child goes further into the sideways approach.

If you find a knife, tell your supervising social worker the same day, and write down exactly what you found and where, in plain factual language. Record what happened, not what you think the child is. Do not go looking for whoever you believe gave it to them. Police advice on moving a knife is to wrap it and make one specific journey in daylight. Many forces run surrender bins, but check with your supervising social worker before you move anything, because the knife may matter to an investigation. Call 999 if anyone is in danger, 101 if not. Crimestoppers takes anonymous information on 0800 555 111.

If your young person is stopped and searched

In London this is a realistic possibility for a teenage boy who has done nothing at all, so decide in advance that being searched is not evidence of anything. The part most carers are never told sits in the Children’s Commissioner’s report on police powers, published in April 2026. Under PACE Code C an appropriate adult must be present when a child is strip searched, unless urgent action is needed to prevent serious harm. The same report found that 35% of the children strip searched were Black, who are around eight times more likely to be strip searched than White children. And of 44 forces, only nine routinely recorded whether the child they searched was in care.

So the system will not reliably know your young person is in care. You have to say it, out loud, every time, and ask who the appropriate adult is before anything else happens. Then tell your supervising social worker, however minor it seemed. A search that goes unrecorded by you is a search that cannot be challenged later.

You won’t have to do this alone

Every Greater London Fostering carer has a supervising social worker who knows the household, and an out of hours number for the evenings when something cannot wait until Monday. The training covers gangs and exploitation properly, rather than in a leaflet. If a young person in your home is being drawn towards something, that is a problem the agency owns alongside you. We were inspected by Ofsted from 21 to 25 July 2025 and rated Outstanding in all three judgements.

Fostering is paid work, and we are open about the figures. As at November 2026 our carers receive 479.50 pounds a week for a child under 11 and 507.50 pounds a week for a child aged 11 or over, paid for each child while they are living with you, with an enhanced fee of roughly 100 to 200 pounds a week more where a young person’s needs are higher. One weekly payment covers the allowance and the reward, so there is nothing to claim back for birthdays or school shoes. If you are weighing up fostering a teenager, the hard days are real and you will not face them alone.

Where to get help

• 999 if someone is in danger, 101 otherwise
• Childline, 0800 1111, free and confidential for anyone under 19
• Victim Support, 0808 16 89 111, free, 24 hours a day in England and Wales
• NSPCC helpline, 0808 800 5000, for any adult worried about a child (check their website for current opening hours)

Frequently asked questions

Does fostering a teenager put my own family at risk?

It is the question almost everyone asks and almost nobody asks out loud, so ask it. We tell you what we know before you say yes, and you can say no. Any known risks go into your safer care agreement, which describes how your household runs rather than labelling a child. If something changes after a young person moves in, it gets reviewed with you rather than left on your shoulders.

Should I search my young person’s room?

Talk to your supervising social worker before you do, not after. Searching a room is covered by your safer care agreement, and done badly it can cost you months of trust for nothing. If you believe there is a weapon in the house, that is a same-day call, not a search you carry out alone.

What happens if my young person is arrested for carrying a knife?

Ring your supervising social worker, and somebody will help you work out what happens next, including who attends the police station as the appropriate adult. An arrest does not automatically mean the young person moves out. Usually the right answer is the opposite: a young person who has just been arrested needs the one home where coming back is still safe. Help with the days after sits in our guide to when a foster child’s behaviour is hard to handle.